The Hvac System To Water Cooled Chiller Engineering Essay

Many studies, empirical research, and energy consultants frequently claim that there may be a large unexploited economic prospect of keeping energy. Usually, this probable is estimated to be in the range of 10 - 20 %. This dissertation explores the determinants which affect the management of energy efficiency in commercial building, and discuss possibilities how to support the exploitation of energy preservation measures.

The theoretical principle is dependant on the ideas of behavioral decision theory and recent research in neuro-scientific organization development. In this particular view, energy related action and decision making in commercial building are developed by capability and the readiness to act of the individual engaged, and by the inner organizational structure, commercial routine and prices.

Conducting the initial energy audit is a critical hurdle for energy efficiency, no matter if the audit is included in an energy management process or a stand alone activity. The original energy audit requires readiness to act, considerable work and an extensive amount of sensible and methodical knowledge and understand how, which commercial building do not possess.

We do the modeling by using the simulate a commercial building. For example, we identify and extensively describe energy preservation steps within building heating up, ventilation and air conditioning (HVAC) system. Considering the conditions of initial energy audit, we modal the measurement in such a way that, apart from basic data no further measurement are required to come to summary. The information necessary is attained using formulation, data tables, rule of thumb, estimation and cover in a simplified calculating costs of labor, material, equipment of HVAC equipment and system and the way to analyze the resultant energy preservation.


Abbreviations, Products and Transformation Factor

List of symbols

Table of Contents

1. Introduction

1. 1 Background

The use of air conditioning in Hong Kong attributes a large proportion in our total electricity ingestion, due generally to its geographic location and financial activities. In 2004, air-con accounted for 30% of the total electricity usage. Our electricity ingestion by air conditioning had a growth around 17% from 1994 to 2004. The usage of air conditioning is expected to grow further because in our increasing populace and financial activities. We therefore need to take options to improve our energy efficiency, in particular, on air conditioning.

Currently, a large amount of energy is being consumed by HVAC systems in complexes. According to the information from the Hong Kong SAR government, about 17% of the full total energy, which is about 30% of the electric energy (Chow 2006) is being consumed by HVAC systems in buildings. Therefore, energy conservation of HVAC systems in structures will evidently have a sizeable impact on total energy ingestion.

Up up to now, a whole lot of efforts have been manufactured in various buildings to reduce the energy ingestion in HVAC systems. For example,

Marriott (2006) suggested three approaches that may be easily applied in structures to improve the energy efficiencies of HVAC systems. The approaches are optimizing the source air temp, recovering energy from condenser normal water and taking a geothermal heating pump system.

According to a study conducted by the EMSD, the energy conservation from numerous kinds of the water-cooled air-con system amounts from 14% to 35%. The capital cost of evaporative water-cooled air-con system is about 15% lower than air-cooled ac system on new system basis. Hence, if the conversion of existing air-cooled air cooling system to evaporative water-cooled air-con system can be designed at the end of monetary life of existing air-cooled air-con system, chances are to truly have a reduction in replacing cost for choosing evaporative water-cooled air-con system in lieu of air-cooled air-con system. The functioning life of air-cooled packed chiller condensers is just about 15 years while for fresh water cooling towers is just about 20 years.

Chan (2006) proposed optimum control reasoning for the HVAC system of a building in Hong Kong, which minimized the mismatch of cooling fill demand and cold water move demand. Around 435, 000 kWh was saved by the developed control reasoning from June 2003 to May 2004.

Mathews et al. (2002) developed a simulation tool, QUICK control. It quotes the effect of different control strategies on the energy preservation performance in various buildings. Effects of control strategies such as enthusiast scheduling, set point setback, economizer cycle, new set in place point, enthusiast control, heat vegetable control, etc. can be looked into at length this simulation tool. Mathews et al. used this simulation tool to review the energy saving potential in a conference center in South African. A new control strategy originated with the aid of this simulation tool. It had been expected that about 58% of the HVAC system energy could be kept.

Chan (2006) and Mathews et al. (2002) proved that aside from the energy efficiency of the machines (chillers, pumps, enthusiasts, etc. ), control strategy also takes on a very important role on HVAC energy use.

Kim et al. (2001) conducted a computational smooth powerful simulation for examining the indoor cooling down/heating load. It had been in conjunction with a radioactive heating copy simulation program and a simulated HVAC control system. The productivity of the simulated HVAC control system can be given back to the boundary condition of the CFD simulation program and the interior environment was simulated. New control sign can then be determined based on the interior environment. Energy saving performance of the control strategy can be investigated accurately. Together with the same simulation program, thermal comfort may also be predicted by the determined indoor position using PMV structured approach.

In this paper, a practical review on energy preservation in a commercial building was completed. Chillers, pumps and the control system were retrofitted based on the examination of the characteristics of commercial building cooling down load. Energy conservation performance of the retrofit was investigated.

1. 2 Research questions

The aim of this dissertation has been to be clarified and prices computed regardless of what the retrofit entails.

What various options are available to rectify this waste material, what is the retrofit cost of every and how much will each save in energy cost?

What is reasonable purchase prices of any equipment needed?

How much labor is required to take away the old one and install the new one

What piping, valve and ductwork change will be needed?

Hoe much labor will be engaged in draining original system, flushing, pressuring, examining and refilling new system and start up?

How much will be needed for balancing and altering the system and monitoring energy costs?

And lastly, the top question, what will the energy conservation be with this approach and what's the payback and profits on return?

It is absolutely necessary to obtain this information and compare the many strategies available and make a wise decision based on correct and complete cost projections and energy preservation.

1. 3 Research objectives

1. 3. 1 Main objective

The main of the target is to factor of perform various retrofit change, estimate the energy conservation and the restoration costs. It provides process and formulas for energy program, audits, engineering and estimating.

1. 3. 2 Specific objective

The focus of the dissertation is positioned on the precise objective is considering energy conservation in HVAC system in the next manner.

Generalities: Start energy conservation program thinking in terms of concepts or generalities and then follow up with particulars. Think about reducing HVAC lots, O & M saving, increasing efficiency of equipment and system, reducing movement, etc.

Specific: After a general concept is created then think in terms of specific heating and cooling equipment, particular HVAC system, piping system, ductwork system, insulation, control, etc.

Load Variation: Consider hoe the building cooling down load can vary greatly scheduled to occupancy, the shifting sun, operations, etc. and about which chilling loads are regular on a regular basis without variation.

Low Cost, COST-FREE Item: Think in terms of no cost, low cost energy conservation measures which is often done easily and quickly and which may have phenomenal payback.

Capital Investment Item: Then think in term of capital investment energy improvement looking for people that have the best energy personal savings and the highest rate return or most effective payback.

Electrical: Distinguish electronic consumption cost of supporters, pumps, chillers, condenser, air conditioning tower, light etc.

1. 4 Research methodology

This dissertation using the regression examination method for establishing the commercial baseline. Regression analysis involves locating the relationship that presents how energy use alters with changes to an independent variable or variables. This relationship can be used to quantify energy use for different prices of the 3rd party variables.

Data is collected over once period and period for the proposed independent factors and the based mostly variable, in this case energy consumption. The data is then analyzed to develop an formula, generally linear, that details the relationship or 'regression lines'. This series is an estimate of the dependant adjustable for prices of the self-employed variable or factors.

Independent parameters that have an effect on energy consumption range from factors such as development rate, product blend, raw material, occupancy and ambient temperature.

1. 5 Composition of the dissertation

Chapter 2 provide overview of existing literature for genuine research procedure for energy saving strategy, thereby providing the foundation complex information for the energy preservation. The chapter begins by estimate the power auditing for the commercial building and then supplies the energy ingestion of the commercial building and a strategy for retrofit cost and examination, financial evaluation.

Chapter 3 addresses research methodology used to create the energy transformation model for the procedure used in this research. In additional to the, data collection for Supplementary data and Primary data are described.

Chapter 4 offers empirical simulation using case studies of real commercial building. This business lead to go over on the task and applicability of the models for auditing, retrofit Cost and Examination, financial Evaluation, as well as an explanation of the energy cost saving that can be obtained because of this.

Chapter 5 concludes the theoretical and the empirical findings and closes the research article by summing up the results and providing ideas for further research.

2. Books Review

2. 1 Energy Audit

The purposed of a power audit is to look for the energy ingestion and cost of overall building and of its specific components, the structure, system and equipment. It is to create energy improvement options, to task energy saving, to estimate the price tag on energy improvement, calculate payback, and upon this basis measure the various options.

The code of practice mentions the audit in Hong Kong. As talk about by EMSD, (2010) the specialized information and details in respect of the power audit requirements under the Ordinance. Energy audits conducted in accordance with this Energy Audit Code are deemed to acquire satisfied the relevant requirements of the Ordinance in the complex aspects. Energy Audit Code is developed by the EMSD together with various professional companies, trade associations, academia and federal departments.

(EMSD 2007) In fact, the guideline of energy audit indications that an efficient energy management tool. By discovering and utilizing the means to achieve energy efficiency and conservation, not only can energy personal savings be achieved, but also equipment/system services life can be lengthened. All these mean cost savings in money.

Based on the theory of "The less energy is consumed, the less fossil fuels will be burnt", the power supply companies will create relatively less pollutants and by-products. Therefore, all gatherings concerned contribute to conserve the surroundings and to improve ecological development.

(International Congress ISPE/PDA Pharmintech 2010) Considering that research study at

Sanofi Midy Research Centre covers a reconstruction of a research centre included the data collection overview of the documentation you'll be able to identify the service disadvantages. The exemplory case of site review for verify the regularity of the records and the identify the major problems to identify areas easier upgradeable

According to recent research by (Robert Greenwald 2004), are presentations the overview of the power audit and performing the vitality audit process included data gathering, power research, inventory and review of equipment performance, measurements and monitoring, identify potential energy conservation measures, analysis of keeping potential, financial evaluation and reporting.

The (Minnesota Legislature and the Governor commissioned the Minnesota Division 2007) of Commerce to utilize the University or college of Minnesota, Minnesota Point out Colleges and Universities (MnSCU), and condition agencies to identify barriers, describe the expenses and great things about actions that could lead to a annual 1. 5 percent energy cost savings energy found in complexes, and develop plan recommendations that could lead to those activities. The report provides qualifications on energy personal savings in government complexes and addresses the questions asked by their state law. It also found that state government-owned properties are a significant potential source of energy savings. The government is in a unique position to take into account the long-term implications of present day decisions. Through leading by example, the government can serve as a platform for the development and execution of energy savings programs, regulations and technologies. That said, there are information, corporation, and resource obstacles to attaining energy personal savings in Minnesota government buildings.


As a corollary (ASHRAE 2011) provide recommendations to design a low-energy-use building which is not a bare minimum code or standard. The Guide provides both multidisciplinary design strategies and prescriptive design deals to significantly reduce energy consumptions in small to medium office properties. Despite the fact that several design packages are provided in the report, this Guide signifies a way, but not the only path, to construct energy-efficient small to medium office complexes with 50% energy cost savings. Energy Standard for Structures Except Low-Rise Residential Structures. Use of this Guide can help in the look of major renovations that take in considerably less energy compared to the least code-compliant design, resulting in lower operating costs. This Guide reveals a broad selection of subject matter, including broad principles such as the designed design process, multidisciplinary design strategies, and design tips and good methods on specific energy systems, as the focus of the Guide, especially the later chapters, is on building and system details that will help achieve the desired results.

(Dr. James Brodrick, 2002) disturb on research of the HVAC literature, recognized 170 technology options that could potentially reduce the energy utilization of HVAC systems in commercial structures. After growing first-cut energy savings potential estimates for each option, 55 options were decided on for further analysis in consultation with a variety of HVAC experts Each of the 55 options received further analysis, including more detailed investigation of their technical energy cost savings potential, current and future economics (cost), obstacles to reaching their full market potential. Many of the 40 technologies have significant specialized energy cost savings potentials. Many of the 15 technologies determined for refined review have significant technical energy savings potential, coupled with attractive or reasonable simple payback durations. Three of your options, Novel Cool Storage space, Variable Refrigerant Size/Flow, and Adaptive/Fuzzy Control, got highly adjustable simple payback cycles that did not readily translate into an average simple payback period, as the simple payback period for Microenvironments exceeded a century.

Except the above energy saving potential of Literature Review, some valuable Specific subject areas are shown as below.

2. 2. 1 Auto Tube Cleaning System

As the condenser can be an important part in the cold water system, the working condition of the condenser is the key factor that impacts the efficiency of the unit. However, the condenser will be seriously deteriorated by the rubble and foul ants accumulated in the tubes of the condensers. When fouling and scaling in the condenser increase, the heat transfer efficiency will be lower, leading to more power usage of the chiller.

The Engineering Division of The Playground Lane hotel identified these problem and began to install an programmed tube cleaning system called "CQM" for chiller in October 2003. The system has been running for a year. Feedback from operators and engineers are good, Inside the COP comparison procedure, the ratio of energy saving was 11. 9% and the average COP was increased from 3. 7 to 4. 2. ( Richmond Consulting Engineers, 2005 ).

Further more, (Wallace Wu & Dave Chan, 2003) proves that estimation the improvement on COP is around 11. 8% and CQM Automatic Pipe Cleaning System can greatly increase the heat copy efficiency of the condenser tube and save significant amount of energy in water cooled chiller. Besides, from the financial analysis, it implies that the payback is less than 2 years.

2. 2. 2 Retrofit of the HVAC system to Drinking water Cooled Chiller

The (EMSD 2000) of HKSAR completed a Preliminary Phase Consultancy Study (PPCS) regarding "Wider Usage of Water-cooled air-con system in Hong Kong" was completed in Apr 1999. The PPCS proven the technological viability of the wider request of WACS and its own financial/environmental benefits. The execution analysis for WACS in Hong Kong was commissioned in 2000 to look at in greater details on complex viability, financial viability, infrastructure works, land use, traffic impact, environmental/health issues, and regulatory control; specifically for nondomestic complexes.

A analysis guide done by HKUST Research, (2005), describe energy saving in a hotel HVAC system was carried out. It included alternative of the chillers and pumps.

In review the retrofit of the hotel HVAC system, the superior energy efficiency resulted from three aspects, i. e. , improved upon energy efficiency of the chillers, upgraded energy efficiency of the pumps and the sensible control system. Checking the COPs of the original and the new chillers, it sometimes appears that the new chillers comes with an energy efficiency about 18% to 36% greater than the initial chillers which might contribute to about 14. 4% to 28. 8% of the full total energy saving. The efficiency of the new pumps is believed to be 30% greater than the original pumps. As the pumps generally ingest about 20% of the total chiller/pump system energy, the replacement of the pumps contributes to about 6% of the full total energy conservation. Then, the remaining 27% to 45% of the energy conservation should result from the brilliant control system. Together with the new system, 63% to 74% of the chiller/pump energy was preserved. The result demonstrates a considerable amount of energy can be saved in hotels with a good control system and high efficiencies of the chillers and pumps.

(Kenny Chan 2009) research says the investigate for sustainable design and life circuit costing considerations in adopting relevant air-conditioning system to appeal to long range planning in facility/maintenance management. Form the study and analysis, transformation from ACAS to WCAS would save around 35% running costs.

2. 2. 3 Changing speed drives

A research study done by ( G Jones 2009) to compares the power intake of the centrifugal enthusiast when driven by the star/delta starter and using variable speed drives to regulate motor speed. Through the initial monitoring of the energy utilization, the centrifugal supporter was controlled by the original star/delta starter. This have been the technique of controlling the fan since the machine was in the beginning installed/ commissioned. After the fan had been jogging for over 390 time the exact run-time and energy utilization was noted. The Electric motor Control Warehouse then changed the superstar/delta starter for a 22kW wide open loop Inverter. After optimizing the Inverter adjustments, the lover was used in normal creation and after about 300 hours, much like the superstar/delta starter the precise run-time and energy utilization was noted. Changing the 22kW centrifugal lover control from a star/delta starter to an Inverter introduced an energy keeping of 41. 3%.

( Lappeenranta x. x. 2008 ) analyses the computation of Admirer and Pump energy conservation tools calculation. With these programs energy intake of variable rate drive control for followers and pumps can be compared to other control methods. With Admirer centrifugal and axial supporters can be reviewed and Pump deals with centrifugal pumps. By means of these programs also ideal rate of recurrence converter can be chosen from the ABB collection.

2. 3 Final result on the books review

The chapters above have talked about the related information for the dissertation to assist estimate, solution, evaluate and keep track of energy cost savings, quantifiable costs and benefits created consequently of employing energy efficiency opportunities.

Specific enhance the understanding of how to forecast and evaluate energy savings, realize energy savings by accurately quantifying the complete of business costs, benefits and payback of energy efficiency opportunities, determine the financial value of an energy efficiency opportunity so that investment quality information is provided to company decision designers and quantify the accuracy range for each stage of the power savings analysis.

3. Methodology

3. 1 Research Methodology

This dissertation is descriptive in character: it aims to spell it out the energy saving of the commercial building. Time smart, it targets the entire year 2009, when the research was completed. Changes in commercial building's energy intake between early studies and today's one are also seen. To construct a thorough picture of the examined phenomenon, today's research used both quantitative and qualitative data and means of analysis.

This study is split into two parts. The theoretical part of the study is a books review. This existing theory was used as a conceptual tool to get a more organized understanding of the power consumption and conserving potential of commercial building. Based on the theoretical part, a short knowledge of the commercial building of energy use was built.

The empirical part of the study contains one circumstance studies that provided energy usage of commercial building and the building description of Category, Heating and cooling system, etc. should be there. The research focused on describing the problem of the challenge with the existing HVAC system and building and suggested energy saving method of renovation.

The data collected in the theoretical part was also employed in the empirical part in estimating the current energy utilization of commercial building.

3. 2 Data Collection

3. 2. 1 Supplementary data collection

Secondary data resources were utilised both in the theoretical part and the empirical part of the study. Most of the sources used in the books review were either article publicized in publications and in industry journals or conference papers which were accessible through the databases of the Public library. In addition, publicly available resources such as reports from EMSD were used. The supplementary data collected for the empirical part contains complex details from device manufacturers' websites.

3. 2. 2 Main data collection

The main data for this research was accumulated used Hong Kong energy efficiency and conservation competition awards were structured by EMSD. We were holding used in the empirical area of the study. To estimate the energy ingestion of the commercial building in Hong Kong. The dissertation consult the competition awards of the energy saving method to used for estimation the energy preservation.

3. 2. 3 Problems related to data collection

The energy analysis was the most difficult area of the data collection stage. This was due to entail much formulation of the questions and lack of wide open source. It proved that did not have such information.

In the device convergence case, the purpose was to compare devices in conditions of

their life cycle energy utilization. However, life circuit energy data was available for

only a few products. Information on the weight of the merchandise was readily available on the manufacturers' internet sites. Subsequently, data from which energy usage could be believed needed to be gathered from various sources, including Manufacturer technological report, product descriptions at Internet suppliers' websites and exterior party sites. However, the data sometimes needed to be completed with knowledgeable guesses.

3. 3 Data analysis

The accumulated data help develop a tactical arrange for energy decisions, just like they would for other key business decisions. A major focus of an energy management plan is doing a self-assessment to recognize energy personal savings opportunities.

4. Results, debate and evaluation

The typical 34 storey Commercial Building situated at Causeway Bay of Hong Kong Island. used as an caste review in this dissertation was built in 1992. Overall the HVAC, electro-mechanical and domestic plumbing system in the building used total $ 8 million for the entire year.

Generate and develop potential energy saving improvement, operation and maintenance correction, reducing flows and resistance of HVAC system, considering more energy efficient equipment and system, lamps, electrical, control, warmth recovery choices, solar, etc. Then, assess the potential energy preservation of the many improvements and calculate the retrofit costs involved. Lastly, assess payback and go back on opportunities.

4. 1 Energy Auditing

An energy audit involves the systematic overview of the energy consuming equipment/systems in a building to identify energy management opportunities, which provides useful information for the building owner to choose and implement energy conservation measures for environmental concern and monetary benefits.

The reason for an energy audit is to look for the energy consumption and costs of the entire building and its specific components, the composition, system and equipment, it is to create energy improvement options, to task energy preservation, to estimate the expense of energy improvement, calculate payback, and upon this basis evaluate the various options.

A good audit is diagnostic in nature, builds up a valid prognosis of the reason for energy wastes, and leads to methodical establish remedies. There are two basic stages phase or type of audit, brief walk through audits and comprehensive information audits, either of the entire building or of only select parts of building.

4. 1. 1 Collecting Building Information

The audit team should then check out collect home elevators the building. The information should include:-

General building characteristics such as floor areas, numbers of end-users, construction details, building orientation, building facade, etc. ;

Technical characteristics of energy consuming equipment/ systems, design conditions and parameters; Building services design article with system schematic diagrams and layout drawings exhibiting system characteristics;

Equipment/system operation data, including data logs of metered parameters on temps, pressure, current, operational time, etc. ;

Record of EMOs already carried out or to be applied;

Record of maximum demand readings;

O&M guides and screening and commissioning (T&C) reports

Energy consumption bills in previous three years.

In general, it ought to be assumed that the building administrator would have information on standard building characteristics and the O&M employees would keep carefully the equipment/system complex and operation records. The audit team should determine the correct gatherings to be contacted for information collection, the need to consult with these gatherings for familiarization of the building, the equipment/ systems to be looked into and data verification and the need to discuss with decided on end-users.

The audit team should consider issuing questionnaires to end-users to acquire home elevators thermal comfort, lighting comfort, operational hours of individual floor surfaces/offices, electrical power equipment and home appliances, etc.

4. 1. 2 Conducting Site Review and Measurement

More activities should include the next actions:-

Proceed to plan the website review for the areas and the equipment/systems to be investigated.

Develop energy audit forms to record the studies.

Plan ahead on the website measurement to complement or verify the info collected. The measurements should focus on equipment/systems that limited information is open to determine their efficiency and equipment/systems that seem to be less productive.

4. 1. 3 Analyzing Data Collected

At this stage of the audit, the audit team has gathered a whole lot of information on:-

Equipment/system characteristics obtained from site studies;

Equipment/system performance data obtained from O&M log bed sheets;

Equipment/system performance data from site measurements; and

Equipment/system working conditions of equipment/systems based on design and/or basic engineering tactics.

Based on the above mentioned, the audit team should display screen and position the guidelines with values and movements that deviate from what would be anticipated or required respectively. They are the actual EMOs. However, they should take into account the examination of the irregularities caused by changes in occupancy or other activities.

4. 1. 4 Costing

To identify the improvement works for the potential EMOs, calculations should be performed to substantiate the improvement works by quantifying energy cost savings. In evaluating the effectiveness of an EMO, the auditor has to determine the payback period, net present well worth or rate of go back.

Most calculations can be done using simple payback way by dividing the EMO's capital cost by the expense of anticipated annual energy conservation to obtain the payback period in years.

However, if there are appreciable deviations between your movements of energy cost and the interest rate or if the administrative centre costs of EMOs should be injected at different stages with different energy personal savings achievable at different times, the audit team may need to execute a life cycle cost diagnosis that can better reveal the cost effectiveness of EMOs.

4. 1. 5 Annual Monthly Energy Consumption Profile

Based on the energy consumption expenses over previous years (ideally 3 or even more), the auditor should calculate the annual energy use of the building. Graphs of energy utilization against different months of the year can be plotted, that a pattern or general style over quite a few years is seen.

These graphs can show normal seasonal fluctuations in energy ingestion. Moreover, any deviations from the tendency are indicator that some equipment/systems had not been operating proficiently as common, which warrant more descriptive studies to recognize if further EMO has been around.

4. 1. 6 The class of an audit

The sophistication of any audit identifies the range and the extent to which investigations should be conducted and which results should be examined. Based on available resources, the scale and kind of building, and the power audit purpose, the auditor should adopt the energy audit of different levels of sophistication.

Under such conditions, there are two types of audits:-

a. ) Walk-through Audit

b. ) Complete Audit

Walk-Through Energy Audit Procedure

Make a short walk through inspection to be acquainted with the building, system, equipment, maintenance, operation, status.

Examine the overall building energy intake history.

List maintenance, cleaning, modification, repair and managing needed to this point. Know what maintenance and repair must be achieved before the fine detail audit can be carried out.

Fill out a "Building and System Explanation" report

Write out a set of existing energy problem

List clear and potential energy conservation improvement. Develop the most promising energy improvement further.

In-Depth Energy Audit Procedure

Field Survey

Make a through inspection of building system and equipment and become thoroughly familiar with them. Have a look at operation, performance, maintenance, breakdown, comfort, problem, etc.

Conduct in depth interview with building personnel. Review maintenance, program, performance, comfort and problem of building, equipment and system.

Become acquainted with actual time of procedure of system and equipment, and the hours of occupancy of the staff.

Energy History

Study and assess at 3 12 months history of the building electro-mechanical and fuel energy consumption. Equate to building use indexes of similar building.

Field Test

Take test reading of genuine flow, temperatures, pressure, rpm, amps, volts, etc. at HVAC equipment.

Check pressure drop across filtration system, coil, strainers, etc. Check outside the house air flow at minimal and maximum.

Seasonal and peak energy calculation

Determine the actual existing seasonal and peak energy usage and efficiencies of specific system and equipment, etc. based on ensure that you other data.

Calculate the top and seasonal heating, cooling tons actually necessary for to meet current conditions for the entire building and different regions of the building. Compare with the design and existing capacities.

Evaluation of energy improvement

List all problems with building, system and equipment.

Generate energy improvement and develop people that have most potential. Create set of improvement.

Calculate the potential energy preservation in term of electrical power consumption and in expense.

Estimate cost of retrofit work

Calculate payback and profits on return.

4. 1. 7 Research and Id of Energy Management Opportunities

This part focuses on the detailed evaluation and recognition of EMOs and should include:-

Comparison on actual performances of equipment/systems against original design (if information available) and/or genuine site measurements for any discrepancies and identify the complexities thereof;

Possible EMOs and equivalent substantiations;

Implementation charges for EMOs (making mention of corresponding reference quantities allocated to the results, detailed calculations, schematics and drawings included as appendix); Comparison on different solutions to the same EMOs, as appropriate;

Initial investment and payback of every EMO in the summary

4. 2 Energy Audit Report

To illustrate the audit survey, a research study is offered in this section. The activities performed for every single step of the vitality audit are briefly description.

4. 2. 1 Building and Tool Data Analysis

The first step in the building energy audit process is to accumulate available information about the energy system and the power use routine of the building. This information was collected before the field survey. Specifically, from the architectural/ mechanised/ electrical drawing and domestic bill, the next information and engineering data were gathering

Category of Structure

Commercial Building

Building Description

Total Gross Floor Area (m2) : Total 32, 607 (office - 26, 408 ; retail - 6, 199)

Number of Storey - Total 34 storey (B2/F, B1/F, G/F, UG/F and 1/F to 33/F)

Description of surfaces:-

i) Car park - B2/F and B1/F

ii) Shop - G/F, UG/F and 1/F

iii) Office - 3/F to 33/F

iv) Facilities rooms - 2/F, roofs

Building Building Detail

Hours of Occupancy and operation

Monday - Sunday (08:00 - 24:00)

Central air-conditioning system

Central air-conditioning resource capacity - Total 1, 640 TR (air-cooled type chiller flower)

Central chiller vegetable system configuration-

The existing system configuration: 4 x 410 TR air-cooled reciprocating type chiller units (using R22)

Central air-conditioning resource (air-side equipment)- 20 nos. of PAUs supply pre-treated air to each tenant units

Electrical services

Electricity supply - 4 nos. of just one 1, 500 kVA electricity supply

Emergency generator 1 no. of 550 kVA generator

Connected electric powered loads

For Water Area equipment of central chiller seed - 41. 9%

PAU for tenant product from 3/F to 33/F - 4. 1%

Fresh and Flush Normal water Pump inside 2/F Pump Room - 1. 9%

PAU for atrium on the escalator install inside 2/F pump room - 0. 5%

Lift No. 1 - (Fireman Lift) - 1. 8%

Lift No. 5, 6 and 7 - (Passage Lift for low area) - 4. 9%

Lift No. 2, 3 and 4 - (Passage Lift for high area) - 3. 5%

Other Include PAU, Ventilation Enthusiast for carpark, general public lighting, general ability, FS Equipment, control room, fresh/ Flush Pump. . etc. - 41. 4%

4. 2. 2 Interview with building personnel.

4. 2. 3 Walk-Through Energy Audit

After a one day field survey was conducted with the assistant of the building operator. Much useful and revealing information and anatomist data were gathered.

Problem with the existing HVAC system

It was discovered that the maintenance is poor. Filtration, coil, condenser pipe and strainers are generally dirty.

It was discover that the energy consumption paying higher demand rate than need be

Air cooled chiller is old and operate in high COP

4. 2. 3 In-Depth Energy Audit

Equipment Schedule (HVAC, Admirer, Pump)

Overall report on all HVAC equipment, air handling units, fans, pumps, chillers are necessary for a concrete detailed view of the machine of the system in the building and easy overview of the their performance.

It is necessary to know the main element design body of the major HVAC equipment as suggested on the plans and standards of flow, pressure, temperature, electric powered, etc. and then to adopt genuine reading to really know what the current figures factually are.

Electrical Intake Graphs

The electrical consumption physique can be punched into a pass on sheet and graphed automatically as shown.

This help greatly to visualize and review the electrical energy situation in term of overall costs, demand charges and KWH monthly. Peaks and valleys are more easily recognized and dealt with.

Electrical Cost per month

Electrical consumption background per month

Electrical Demand per month

Electrical KWH per month

Electrical Load

Electrical Consumption

Equipment test report

Detailed test statement for every major device in the building involved with the vitality audit and retrofit are extremely important for accuracy, auditing, redesigning and monitoring later.

Test report is necessary on major equipment such as supporters, chiller, and condensers.

Electrical load per system

This valuable form lists the electric powered loads and costs independently for each and every system in the building and allows to conclude the full total for all the figures and provides an easy overview of the machine in recap form.

Recap of most electrical loads

This form summarizes all the electronic loads in the building or in the sophisticated, from all options, not only major HVAC equipment.

It are the total loads from lighting, air handling equipment, air conditioning equipment, computer, office equipment, equipment. The total from this sheet get used in the building and system explanation form.

Cooling Load calculation form

The original air conditioning load calculations and capacity HVAC equipment chosen at the time, may have greatly modified over the entire year and new air conditioning load calculations are needed located in the genuine current conditions, to finish up with reliable energy retrofit program.

Peak Chilling CFM per Area

This is very valuable form shows the optimum cooling tons for the main areas in the building and the amount of CFM in each area. The proper execution may be used to examine the initial design or what the current loads are actually, in order to analyze and find areas waste and then to do calculations based in energy preservation proposals.

4. 3 Evaluation of energy conservation Opportunities

Base on the analysis of energy use pattern of the building, several energy saving opportunities for the building were analyzed. Among the energy conservation opportunities consideration in the analysis, a few of them efficiently reduced energy consumption.

4. 3. 1 Install automatic pipe cleaning system for central chiller.

As the condenser is the key aspect in chiller, the functioning condition of the condenser is the key factor that affects the efficiency of the unit. However, the condenser will be seriously deteriorated by the rubble and foul ants gathered in the tubes of the condensers immediately after the unit comes into working. When fouling and scaling in the condenser increase, the power consumption of chiller increase too, as effect the efficiency of chiller will lower.

4. 3. 2 Energy Recovery Temperature Exchangers for Ventilation

Air to air energy recovery high temperature exchangers can significantly decrease the energy needed to cool and heat up ventilation make-up air. The technology is affordable, with payback cycles ranging from below 12 months to 3 years generally in most applications. The technology can be utilized effectively in virtually any building that is reasonably tightly built, with the return/exhaust air duct(s) located near to the new make-up air intake(s). Currently, ERVs are given in mere about 1% of the actual applications, so a large untapped potential for energy saving is available with this current technology.

4. 3. 3 Improved Duct Sealing

Duct leakage is a significant source of lost energy in HVAC systems and both poor workmanship and failing of seals donate to leaky ductwork. Aerosol duct closing systems effectively seal existing leaks but do not promise that the seals won't fail in the future - particularly if the ductwork was improperly reinforced - and the bones pull apart over time scheduled to thermal and pressure cycling. To lessen energy loss from duct leakage, future initiatives should focus on improving the grade of duct assembly.

4. 3. 4 Radiant Ceiling Cooling / Chilled Beam

Buildings with radiant ceiling air conditioning systems, also known as "chilled beam" systems, cool the room via natural convection and radioactive heating transfer. As known by Mumma (2001b), current systems more often than not require dedicated outdoor air systems (DOAS) and tight building envelopes to control humidity. Energy conservation are noticed by significant reductions in air moving ability (only the outdoor make-up air is distributed to the building) and the bigger evaporator heat range of the chiller providing cool water to the chilled ceiling panels.

4. 3. 5 Adjustable Refrigerant Volume/Flow

Variable Refrigerant Volume level, or VRVTM, systems are ductless commercial HVAC systems that may be configured in an extremely flexible manner by coordinating numerous (e. g. , up to 16) indoor evaporator systems of differing capacity and design with a single condensing unit. Currently widely applied in large buildings such as offices and hospitals beyond your U. S. , especially in Japan and European countries, these systems are just starting to be unveiled in the U. S. The systems use multiple compressors, including inverter-driven variable speed products, and deliver excellent part-load performance and zoned temperature control, resulting in excellent occupant comfort. Both installed costs and energy operating costs are highly application centered, and current simulation tools are probably inadequate to accurately capture the true energy cost savings potential of VRVTM systems. The simplest way to address these cost and performance issues is always to perform rigorous field tests evaluating those to the best available conventional systems in various real-world structures and functioning conditions.

4. 3. 6 Water-cooled Air- Fitness System ("WACS") to replace the prevailing air-cooled chiller plant

There is definitely shortage of energy resources. Before new sources of energy could be developed, saving would be the only means to safeguard humans on earth. To improve the air-conditioning seed efficiency is one attainable way to go ahead. Form the above research and analysis, change from ACAS to WCAS would save around 35% operating costs.

4. 3. 7 Install Variable Air Volume System

The primary benefit for VAV over continuous amount systems (CV) is its ability to simultaneously supply the required degree of cooling to any number of zones within a building. VAV systems can be especially energy efficient because of this of their capacity to operate the main supply/extract lover(s) at reduced speeds for a lot of the year, when the overall level of air required by the various zones is low (enthusiasts are generally the most significant user of energy in a centralized air system).

4. 3. 8 Install Variable speed drive

At a time of increasing energy cost, using adjustable speed drives to control motor speed instead of the traditional fixed speed direct on line, superstar/delta starters or soft starters can save money and energy.

4. 3. 9 Summation of energy saving Opportunities

To take into account the factor of energy conservation opportunities, it ought to be included the research of HVAC retrofit energy use and the financial evaluation. The details is listed as below.

Analysis of HVAC Retrofit energy consumption

Estimate is determined labor, material and over head cost on the project and coming up with a reasonably exact total price which properly reflects the final genuine costs of materials and labor of this project.

Calculate the energy saving in electric and in cost

Estimate cost of retrofit work

Financial Evaluations

The purpose of the next financial evaluation is to ascertain payback periods, profits on return and rates of come back. The includes first costs, operation and maintenance cost, depreciation, taxes, energy saving, present prices, future values, interest rates, time period and salvage principles.

Simple Payback

Return on investment

Present Value

Rate of come back, life circuit discount

4. 4. Recommendation

According to the aforementioned evaluation of the energy conservation opportunities, the go for three system to be adopt in the first stage foundation on the energy conservation and the payback period. The facts of the machine are listed below.

4. 4. 1 Install computerized pipe cleaning system for central chiller.


After alteration the chiller system from air cooled chiller to drinking water cooled chiller, it produced another energy saving opportunity.

As the condenser is an important aspect in the cold water system, the operating condition of the condenser is the key factor that affects the efficiency of the unit. However, the condenser will be very seriously deteriorated by the dirt and foul ants accumulated in the tubes of the condensers. When fouling and scaling in the condenser increase, heat copy efficiency will be decrease, resulting in more power usage of the chiller.

To solve the aforementioned problem, mount an automatic pipe cleaning system can be considered a solution to handling this problem, the good thing about this system is the refrigerant heat is nearer to the condenser normal water leaving heat than before and Less frequent for manual cleaning. From the above facts, operation cost of the condenser will be lower. In fact, the condenser is retaining its cleanliness, therefore the heat copy is more efficient which result is energy preservation.

Automatic pipe cleaning system vs. Manual Off-line Cleaning





Continuously operating

at maximum efficiency.

Performance gradually

decreases between treatments.


No shutdown normally.

On-line cleaning.

Requires shutdown for cleaning.


No chemicals.

No residues.

Cleaning chemicals & residues

harmful to environment.



Fully intelligent.

Effortless maintenance.

High anticipated to performance

monitoring & manual cleaning.

System Description

In this task, it used water injection system. THE Injections and Drain System uses to its advantage the fact that the pressure in the heat exchanger main shop is greater than that of the inlet, (circulation pump is installed after the heat exchanger). It is suitable for low and high-pressure systems.

The sponge balls are injected by drinking water pressure through the check valve into the main inlet of the heat exchanger. The balls go back to the collector through the check valve. The routine is fully computerized and manipulated by the PLC commander. The system involves two programmed valves, the first, a 40mm ball valve that control buttons water injection, the second 25mm ball valve that controls the drain. The depth scheme is shown as below.

Automatics Cleaning System Scheme

Analysis Approach

The improvement of energy efficiency in energy management for chiller can be involved with the Coefficient of Performance (COP). The strategy found in this report to review the improvement of COP after the installing automatics pipe cleaning system. The provider supply the data on chiller operation were accumulated before and after

the automatics cleaning system assembly which enable the study of success of the machine in increasing the working condition and in reducing energy used.

Assume Chiller No. 1 is the main one installed with automatics tube cleaning system and Chiller No. 2 is the the one that without automatics pipe cleaning system. In this process, we will compare the COP of Chiller No. 1 and Chiller No. 2. Both chillers' capacity is

450 TR, and put into operation almost at same time. We presume that both Chiller No. 1 and Chiller No. 2 are jogging at the same efficiency when without automatics cleaning system.

The average percentage of energy preservation can be calculated using the following formula

By the definition of coefficient of performance (COP) - chilling, it's the ratio of the pace of temperature removal to the rate of energy input. The next equations shall be used to calculate the COP:-


M = Mass flow rate of cold water (kg/s)

C = Specific temperature capacity of water (kJ/kg)

T e = Going into chilled water temperatures ( o C)

T l = Going out of chilled water heat ( o C)

WD = Power Intake of Chiller (kW)

V = Voltage (V)

I = Current (A)

PF = Electricity Factor

We expect that the PF = 0. 9 and constant M = 70 for the above.

Logged data received by manufacturer's data from October 2003 to Sept 2004 of the above mentioned parameters for Chiller No. 2 and Chiller No. 1 were collected for the research.

Result and Analysis

COP can be compared when the both Chiller No. 1 and Chiller No. 2 are operating at the same conditions. Chiller No. 1 is installed with automated tube cleaning system, and Chiller No. 2 is without automatic tube cleaning system.

According to Figure 1, the COP of Chiller No. 1 with automated pipe cleaning system, is normally above that of Chiller No. 2 without automated tube cleaning system,

By using equations (2) & (3), the calculated average COP for Chiller #3 is 3. 7 and the average

COP for Chiller #1 is 4. 2.

Thus, by equation (1), the common percentage of energy preservation = 11. 9%

On the other palm, the effectiveness of automatics pipe cleaning system can be easily realized by checking the Condenser Refrigerant Temp (CRT) and Going out of Condensing Water Heat range (LCWT) Variations. The stand below summarizes the above findings.

The conditions difference decreased to 3. 8 0 C after programmed pipe cleaning system unit installation. It drops about 36. 7% in comparison with the chiller No. 2 that without automatic pipe cleaning system assembly. The narrowing in temps difference implies heat copy efficiency between condensing normal water and refrigerant was greatly increased.

In general, automatic tube cleaning system helps in preserving the cleanliness of the

Condenser Products, thus keeping the peak efficiency of the chiller and therefore save energy.

Payback Analysis

From these analysis, we can easily see that automatics tube cleaning system give a significant improvement on COP. The projected energy conservation can be believed by the following formula

Annual ENERGY CONSERVATION = Rated Vitality Suggestions x working hour each day x business days per time x diversity factor x Electricity fee x % cutting down on COP


Working hour each day = 12 hours

Working days per calendar year = 5 1/2 days * 52 weeks = 286

Diversity Factor = 0. 5

Electricity fee = HK$ 0. 94 per kwh

Simple Payback Period = Cost of automatics pipe cleaning system / (Annual energy conservation - total annual maintenance)


From the above analysis, it demonstrates that Automatic Tube Cleaning System can greatly increase the heat transfer efficiency of the condenser tube and save significant amount of energy in water-cooled chiller. Besides, from the financial analysis, it shows that the payback is significantly less than 2 years.

4. 4. 2 Water-cooled Air- Fitness System ("WACS") to replace the existing air-cooled chiller plant


As explain, over 40% of total electrical energy is believed to be consumed by water aspect equipment in central chiller flower. Make reference to EMSD information, water cooled air-conditioning systems (WACS) will be more energy conserving than their normal air-cooled counterparts.

In large size commercial building, the central A/C system can mainly be split into two parts, i. e. air-side and normal water area. The components in the air-side include AHU, PAU and FCU. Heat and moisture of conditioned space will be soaked up and recinded to get the designed temp by the air-side equipment. The heat ingested through the air-side components will be transferred to the water-side; and turned down to atmospheric air or water. Heat rejection component of the water-side (condenser product) is classified as normal water type and air type. Higher condensing temperature would lead the compressor doing more work to create the same cooling down effect, giving a lesser performance and a higher operating cost.

System Description

Water cooled chillers use less energy used than their air cooled counterparts. Yet, the flow of chilled water to room equipment, including the fan coil systems, or air handling items is the same for both types of chiller. The main difference between an air cooled chiller and a normal water cooled chiller is the method of heating rejection - as the name advises instead of air being used for air conditioning water is used.

Water cooled chillers do not have large V coils, and supporters found in air cooled chillers, so they are in physical form much smaller, and do not have warmth rejection enthusiasts like air cooled chillers to release the waste warmth, instead they are really connected to a device called a air conditioning tower that delivers a moist evaporative process to handle heat rejection from the chiller to the exterior air.

Water cooled chiller performance vs Air cooled chiller performance

Water Cooled Chiller Operation and Maintenance

Whilst the jogging cost is leaner, with drinking water cooled chillers, their necessary air conditioning towers require active management, and really should not be run without regular maintenance. To reject heating, water is passed through a air conditioning tower where a portion of it evaporates, thus chilling the remaining water. A particular cooling down tower's efficiency at transferring heat depends on normal water flow rate, water temp, and ambient damp bulb. The temperatures difference between your water entering and departing the cooling tower is the range. The heat range difference between your leaving water temps and the stepping into wet-bulb heat is the approach.

The operation and maintenance of the cooling tower is vital the chiller performance since in addition to their primary purpose chilling the condenser normal water, they are successful air cleaners.

A large quantity of outdoor air is circulated through the cooling down tower and mid-air is scrubbed cleaning the air, which means the dust and mud in the air is now deposited in to the cooling tower normal water, this varieties muds and sludge which gather in the chilling tower fill and the basin, these must be property cured and cleaned.

Because it can be an evaporative process the amount of chemical substance elements and solids increase as time passes, therefore normal water treatment protocols are needed to monitor and control water quality.

Analysis Approach

The air-conditioning for the shop and office was provided through a complete of

1640 RT air-cooled air-conditioning system (4nos. 340RT; 2nos. 100RT & 1nos. 80RT) installed on podium.

Substantial noises/hot emission/nuisance was created. Silencer was later on installed to lessen the noise, but it addittionally deterred the heat emission from the machine and eventually reduces the A/C's overall efficiency. Due to space constrain, it was required to demolish the existing chiller to provide space for the new WCAS.

Payback Analysis


From the above mentioned analysis, it shows that normal water cooled chiller can save around 35% running costs. Besides, from the economical analysis, it implies that the payback is less than 5 years.

4. 4. 3 Install Variable velocity drive on chiller compressor


Induction motors that typically used for compressors and admirers in air-con systems are measured to handle maximum insert under worst case conditions and then going out of them to perform at full electric power. They are fundamentally fixed-speed motors. Their quickness depends upon the constant regularity of the energy source (typically 50 or 60 Hz).

Variable acceleration drives (VSD) or consistency inverters are solid-state devices and save energy whenever electric motors run at significantly less than full electricity. VSD is truly a frequency converter where 50Hz or 60Hz ac type voltage is first rectified into dc which is then modified back to variable-frequency ac voltage. It must be mentioned that the power demand of motor varies with the cube of the motor velocity, i. e. electricity is proportional to (speed) 3.

This means a reduction of velocity by 20% will lead to reduction of ability consumption by almost a 1 / 2, i. e. 50% keeping. Since most HVAC equipment hardly ever runs at full electricity, significant energy cost savings can be made with these adjustable quickness drives.

Motor Energy Saving with VSD

System Description

The motors on chillers, pumps, cooling down towers and admirers account for a tremendous portion of the energy intake in HVAC system. The usage of retrofit variable speed drives (VSD) is one of the very most effective solutions applied in recent years. The VSD can be added on to conventional equipment or can be part of the factory-supplied equipment. The detail of quality are shown as below.

Without VSD

With VSD

Primary Air-handling Unit (PAU)

PAU fan engine without VSD operates at constant quickness, disregarding the real demand.

PAU fan motor unit is regulated by the real fresh air demand, ensuring to save energy partly insert condition.

Variable Air Quantity (VAV) Air-handling Device (AHU)

AHU fan motor unit runs at frequent speed, airflow regulated by Inlet Guide Vane (IGV) or Outlet Damper (OD), hence increases the resistance in the air course.

AHU fan engine with VSD removes the IGV and OD, keeping energy through coordinating airflow to real demand.

Secondary Chilled Water Circuit

Secondary cold water pump motor without VSD operates at a continuous speed, excess cold water movement at part fill condition will be flown through the bypass pipe.

The rate is regulated based on the differential pressure over the supply and give back cold water pipes, saving energy as the move of excess chilled water is reduced.

Analysis Approach

VSD for PAU (Major Air-handing Product)

Conventional Main Air Handling Products (PAUs) usually pre-treat outdoor air at a constant air amount (i. e. CAV). The PAUs supply air to different areas in the building at a constant air flow rate of full load condition, disregard the actual demand. This can waste materials energy because the PAUs operate at part insert rather than full load in most of the time.

Demand control on PAUs using skin tightening and (CO2) provides unique opportunity to resolve the challenge of how to lessen energy costs while optimizing indoors quality of air.

CO2 control is most beneficial applied to spots with varying or intermittent occupancy.

Typical Design of variable movement PAU using VSD & CO2 sensors

VSD for Chilled Water Circuit

In cold water system, the principal loop includes primary pump sized to circulate the cold water through the chiller and the rest of the main piping loop. The secondary chiller drinking water loop, which consists of extra pump, is a adjustable flow system. Chilled water is circulated by the supplementary pump through the control valves and chilling loads linked to the circuit. However, almost all of the control valves in the circuit aren't fully wide open because of part load in almost all of the time. Therefore, the cold water stream in the extra normal water loop can be regulated by VSD to handle the chilled water required by the chilling load, thus to save energy.

Variable Chilled Water Movement System using VSD

Result and Analysis

With damper control, the insight electric power reduces as the circulation rate decreases, however under VSD control the energy reduction is far more dramatic. The adjustable torque feature of the enthusiast means that the partnership between stream and the speed of the enthusiast is such that the input ability reduces in a cube law romance with the acceleration decrease, as shown in the graph. Changing speed supporter control can be applied in a wide variety of applications including most types of air flow systems, air draw out systems, industrial air conditioning, and combustion-air control systems for boilers. One of the limitations of VSDs is that it's not normally possible to lessen the flow completely to zero due to a reduction of air conditioning capacity in the motor; a minimum spee

Also We Can Offer!

Other services that we offer

If you don’t see the necessary subject, paper type, or topic in our list of available services and examples, don’t worry! We have a number of other academic disciplines to suit the needs of anyone who visits this website looking for help.

How to ...

We made your life easier with putting together a big number of articles and guidelines on how to plan and write different types of assignments (Essay, Research Paper, Dissertation etc)