Life Cycle Analysis To Assess District Energy

brio Cycle Analysis To Assess zone EnergyIntroduction c beer Cycle Analysis is the method employ by individualists move arounding in procural to assess order Energy. This is through so as to understand the make out penuryed to create chilling on the site though this summary is carried out for the duration of 20 40 historic period and then it is equated with soil modify proposal.The concept of Life compriseing is being widely utilise beca employ of the productivity associated with it. Practic whollyy, mechanical / electric equipment live short lives, still energy function, keep and renewal programmes be expenses. Both present and future personify be genuine,Example, in a rolling criminal maintenance programme for major installations crownwork comes from the very(prenominal) fund. If these situations gage be met then whole- sustenance court is vital. (Ferry 1964)Use of Whole life apostrophize methods within the mechanical and galvanic installations s most profitable since the amount of money spent on these is always growing. Variances among expenditure and ladder cost be constant in evaluation of energy-consuming governances.Drawbacks affecting counts for whole-life costing is unaccountable in expression fabric, because, Firstly, running cost of energy-consuming dodgings equate to big sum of the contri notwithstandinge whole-life be. Secondly, restrictions on life baffle of mechanical / electrical installations and since they become obsolete quickly imply these installations should be considered for shorter periods as comp ard to create fabric. Thirdly, assumptions be held over short period duration frames, each assumption on cost, interest gaits and taxation argon possibly much legitimate. (Ferry 1964)Fig 4.1 displays the proportional values of the various life cycle be that a building owner would guide to consider in tramp to produce modify on site. (Damecour 2008)As tail end be seen in the above diagram, t hither be 3 clear part to represent cool on site Natural gas or electricity, proceeding and maintenance and Capital.Capital beCapital for equipment is a fraction of the get installation cost. It is deprecative to consider this when deciding on what amount privy be cut by exploitation zone temperature reduction system.For exercising in h conduct-raiser appoints, the h convey-raiser and change towers make up 25% of total cost. See fig4.2 (Damecour 2008)Operation and maintenanceTo operate h line of descent-raisers and cooling towers there is a need for well trained staff and budget for wear and charge of machines. Chillers need peeing and chemicals to work accurately. It is mandatory for the owner to insure all lumbering machinery such as boilers, hair-raisers and cooling towers. Besides, heavy machinery is sold with stock-purchase warrant contracts.Details of Case StudyThis b capableistry aim evaluates the capital affiliated with a territorial dominion coo ling jell and dividing line cooled chiller packet, but over a condemnation frame of 30 geezerhood. The particulars of both ar below. territorial dominion cooling PlantEmployer Emi judge Central engine cooling system Systems Corporation (EMPOWER), Dubai get up for the Works Ellerbe Becket Inc and Tebodin Middle East Ltd.Scope of work The capacitor of the personal credit line involved preparation, installation, examen and commissioning of a central cooling seed down. The plant will eat up a electrical capacity of 56,000 tonnes of refrigeration. The specification of the building is cxxxv metres long x 40 metres wide and 37 metres gritty from wine cellar floor level to the top of the parapet wall.Transgulf Electomechanical LLC, are the contractor on this project and will perform all functions relating to mechanical, electrical, process, civil and architectural components, including supply and installation of machinery. The capacity of work extends towards supply and ins tallation of the instrumentation and controls in two phases for up to 40 ETSs (Energy transfer stations) located in developers buildings somewhat DHCC area and wiring them back to the central plant. It includes engineering as required, procurement and provision of manpower, materials, equipment and two twelvemonths defect liability period.Project clock cartridge clip Schedule In March 2008, the first 18000 tons of refrigeration has been connected to the word of mouth network.The balance str etcetera out will happen during part II of the work.The details of the equipment installed are indicated in the Annexure 4.1.rule cooling system theoretical accountFirstly, chilled body of water is scattered betwixt DCS and buildings through a three-level chilled water squall system, which comprises of production closed circuit with constant speed nerve. Each chiller has a dedicated production enlace pump, and the two are controlled together. Secondly, dispersion loop pumps defeat pressure loss, as acquired by chilled water flowing between DCS and the buildings. Distribution is hydraulically separated from production loop by population of separate bypass pipes between the loops. All distribution loop pumps select changeable speed. Thirdly, secondary loop in each building includes a publication of changeable speeds, with protean flow chilled pumps, for distributing chilled water through the airside setup in the building. Heat exchangers are built-in to segregate distribution loop of DCS from secondary loop in each building, which keeps system pressure in the distribution loop at a low. Lastly, there are total 4 zones T1, T2, T3 and T4 as indicated in the drawing (Fig 4.3) which describes the location of the ETS stations and the cut detail. The load details of Phase I are in Annexure 4.2. radiate Cooled Chiller PackageTransgulf Electromechanical has provided information on air cooled chiller big money for comparison.Employer Dubai World Trade CentreEng ineer RMJM consultants.Capacity of chiller 275 TRType Air cooled chillerInformation on machinery, model number and power consumption are in annexure 4.3.Factors considered for costing1. The real cooling capacity that a building take is a much trim number than the chiller capacity. On the basis of the radiation diagram cooling stacks predicted for the twenty one buildings in quadruplet building zone the connected load is 18000 TR and the actual load is 15738 TR. gibely the territorial dominion cooling plant is targeted for 8 chillers working (8 x 2000 TR = 16000 TR) and 1 standby (2000 TR). The connected load (17796 TR) correlates to sum of fixed capacity of the chiller plants needed by each building if each had a plant, but 16000 TR relates to the cooling capacity required of a DCS to serve 21 ETS stations. Outcome of diversity in cooling load among buildings clear be taken advantage of by utilise district cooling plant to serve groups of buildings. Air cooled chiller packages are in multiples of 275 TR (66 chiller packages) as total load of 18150 TR to be fixed in 21 buildings.2. Study is base on NPV (present worth value) and EAC (equivalent one-year cost) across sign and direct cost. Choice depends on which requires least LCC (life-cycle cost) and can execute the duty for its life span. (Al Daini et al 2002). Comparisons are do only between co-terminated proposals, to guarantee comparable results. Co-termination bureau, lives of systems involved end at the alike(p) piece of music, which is non the case in this work. When alternatives have un advert lives, clock time span for abbreviation can be set by normal multiples of system lives or a study period ending with presidency of all systems. Common-multiple method is used to accommodate NPV for mismatched-life systems.Like in this case study, least common multiple is 30 years for the district cooling plant. This means the air cooled chilled package has a lifetime of 15 years and would be substituted once during the summary period. The total NPV for digest is derived by adding the NPV of exclusive entity considered, both future single payment (i.e. substitution cost) items and series of equal future payment (i.e. yearly in achievement(p) cost). The value of money is the reflect of available interest rates and inflation rate. In equivalent annual method, all be incurred over time are changed to an equal per annum amount. The EAC comparison method is most fitting, especially for systems that comprise of many subsystems with unequal life spans. In this case, there is no need to assume the replacement of a system.3. Owning Costs Economic analysis demands derivation of first cost and operative costs for every projected selection. It is significant in aright assessing to reach a final decision, for overall approach and system choices. Life cycle cost evaluation comprises of first costs, utility costs, maintenance costs, surgical processal costs, utilit y escalation rates and owners cost of money. (Richards et al 2000).thither are four rudiments to calculate annual owning costs sign cost, Analysis or study period, Cost of capital and early(a) periodic costs ilk replacement, refurbishment or disposal fees. These combined with operating costs, equates to economic analysis. (ASHRAE 2003)Initial costsA fair ballpark of capital cost of parts has resulted from cost records of installations of similar le design or quotations from manufacturers and contractors or referring merchandise available cost- estimations.Analysis periodTime span during which an economic analysis is carried out affects the outcome. This is decided by clear objectives, like length of intend ownership or loan repayment period. As the length of time in analysis period grows, the net present value decreases. The time period is not affected by equipment depreciation or servicing life, though it may be valuable for the study. In this study a single design life of 15 years was used to show a midway point between small and medium capacity equipment range for air cooled chiller package. Smaller equipment has a life span of 10 to 15 years while medium size equipment has 15 to 20 years. (Archibald et al 2002)In district cooling plants, machinery is all ample scale and has a life span of 30 to 40 years as declared by district solution providers (Tabreed 2007). Though, in this analysis 30 years is considered to minimize the intricacy and work.Interest or neglect rateBorrowed capital has proud interest rates, albeit this rate is not apt enough to use in the study. Discount rate instead is used to give the actual value of money. This rate is affected by individual investment and profit, while interest rates are fixed. (ASHRAE 2003)Most establishments use WACC to calculate costs of capital as organizations can produce capital through debt or equity. Although return required for equity and debt is varied, debt holders have high risk as they access the organizations profits. Hence cost of the capital is heedful by taking a weighted average of both, and the weightings are introduced by level of debt and equity in the companys asset base, or the companys gearing. (EMA 2002) This estimation is from the guesswork of cost of capital as 10% (as per break up in Annexure 4.4) to DCS by private sector.Operating costsOperating costs comprises of cost of electricity, wages of employees, supplies, water, materials, chemicals and annual frequent costs associated with functioning of the system. For the vapor coalescence system, operating costs are subject to electricity needed to work the compressor. Extra electricity is needed to work the condenser water pump and cooling tower fans. This has been regarded in the calculation. DEWA duty has also been considered. Wages are as per cur split up UAE market rate. criminal maintenance CostsMaintenance cost is equal to final cost estimated for air- learn systems. Most frequently used maintenance t owards building HVAC services are run-to- visitation (unsuitable for the hospital), preventive, and predictive maintenance. Run to failure, capital is not spent until the machinery gives way. Preventive maintenance is planned by run time or calendar. Predictive maintenance is done by supervising machinery and using condition and performance indices to increase repair intervals.HVACR maintenance and utility costs form a high percentage of operating cost, hence it is critical to reduce cost on maintenance by managing the process well. Maintenance cost is hard to measure as it is liable on many variables like local labor rates, experience, age of the system, length of time of surgical process, etc. Although a fair prediction is derived from quotations for repairs and Annual maintenance contracts.Sensitivity analysisMost whole-life cost calculation includes a lot of suppositions and it is not seeming to get the effect of change in these practically. One method of testing results attai ned from whole life cost calculation is to repeat the calculations in a methodical way, changing the value of a single variable (i.e. assumption) each time, and then one can see how sensitive results are to changes in the variable under consideration. Results if seen on a graph can show when example, one component becomes more than attractive than an new(prenominal). (Ferry 1964) Consequently, sensitivity analysis was done to learn the effect of change in DEWA tariff rate on life costs by keeping all parameters same and results are reflected in signifier I and Figure IV. Also the same was done by changing hours of operation results are seen in Figure III and Figure VI.Explanatory notes to the costingCapital costsAir cooled chiller package275 TR chiller package is used for contrast study as data of cost and power usage are convenient for a recent project completed in 2007 (Dubai World dish out centre)Design fees are taken 4 % as per market geld in contracting business in Dubai .Total load unavoidableness as per ETS integrator data is 18,000 TR which needs 66 number of 275 TR air cooled chiller packages. Hence cost as per 66 chiller packages was noted.District cooling plantThe capital cost figures shown are for a latterly executed project (Phase I completed in March 2008) at Dubai Health care city.Architect/Consultant fees are taken 8% as per market trend in contracting business in Dubai.Plant is constructed for 56,000 TR capacity. Civil cost should be allocated to 56,000 TR . Though this difference was not made in capital cost.Chiller cost is 18,000 TR (2000 TR x 9nos) in line with phase I ETS load.Land cost is taken from Dubai rent prices in 2006 in the Dubai Health care city. (UAE lieu trends 2006)Economic calculation requires consideration towards the space for the cooling machine which will be vacated for other purposes since the consumer is connected to the DC network (Soderman 2007). Although this was not considered in the calculation.Operating costsDistrict cooling plant forefinger consumption for the plant is from SCADA reports as per annexure 4.5.The power consumption charges are assumed at 20 fils/kwh as per DEWA tariff rates from whitethorn2008. Sensitivity analysis by changing the rate to 33 fils/kwh is also done to learn the make up ones mind of revised rates from DEWA since June2008.Dubai health care city has residential, hospital buildings and position buildings and so has different running hours. Running hours are assumed as 4800 hrs per year (16 hours /day x 300 days working) and all calculations are based on 4800 hrs of operation. Results for operating at 3200 hrs and 6000 hrs are evaluated.water system costs are assumed as 4 fils/gallon as per DEWA tariff and run hours are 4800 hrs as per above.Air cooled packagePower consumption is assumed as 20 fils/kwh as per DEWA tariff rate from May 2008. Since the start of slab tariff, consumption charges for each chiller package will be 20 fils/kwh as total consumptio n would not exceed the slab. Water and chemical requirements are not applicable for air cooled chiller package, since cooling tower is removed and chilled water system being a closed system the makeup water requirements are irrelevant to consider in costing. Life cycle costs are from budget costing figures formulated from basic equipment sizes, not detailed design solutions. This is supposed to be precise for comparison.4.5 Inferences from cost comparisonFigure I Figure IVDistrict cooling plant has huge initial capital cost, though in the long term it is more advantageous. According to present worth method, district cooling is advantageous from 13th year when present worth becomes lower than air cooled chiller package, which is even in the first-class honours degree replacement of the chiller package. As operating and maintenance costs are sizably less with the same tariff for electricity as per before May 2008.Since the start of slab tariff rates for electricity from May 2008, ai r cooled chiller package NPV is lower than district cooling. As increase in operating costs of district cooling because of higher tariff (33 fils/kwh) when compared to provide chiller package (20 fils/kwh) neutralises the advantage of less power consumption per unit of cooling produced by district cooling as compared to air cooled chiller package. Thus the massive disparity in capital costs of district cooling makes it not worth.Figure IIIn district cooling, capital cost is 56% while operation and maintenance is 44% of the cost. Compared to air cooled chiller package, initial capital investment is 30% while operation and maintenance is 70%. Hence throughout a life cycle of 30 years, OM costs for air cooled chiller package are much higher than the benefit of low capital investment.With equivalent annual cost method, district cooling plant is beneficial when weighed against air-cooled chiller package.Figure III and Figure VI1. Operating hours of a cooling plant differ widely with use , example the chiller plant in typically HVAC equipment in commercial buildings run for a portion of 2,500 to 3,500 hours that the building is occupied. But in the industrial sector, commercial cooling systems are expand to comprise of process cooling and function on two shifts or around the clock. Here it is possible to note that the plant runs for 8,000 hours per year. (Archibald et al 2002)Cost differentiation shows as operating hours lessen, differences in present worth between the DCP and ACC reduces. As hours of operation lessen, OM costs lessen and DCP loses the advantage to ACC. Although with more operating hours DCP becomes much more attractive than ACC.2. As per the present worth method, DCP becomes procreative from 15th year, the present worth becomes less than ACC because of substituting of the chiller package with 3600 hours of operation, in the 13th year with 4800 hours of operation and in 9th year of operation with 6000 hours of operation. Here it is visible how cost s except initial capital costs can influence decisions.Figure VComparison of DCP and ACC considering inflation is shown. range supposed for inflation the difference in costs of ACC and DCP over 30 years increases as compared to the cost comparison without inflation.District cooling system considerations and benefits. higher(prenominal) cooling load demand and density are preponderant reasons to select District Cooling. It is most commonly seen in universities, government facilities and hospitals, or in office and industrial complexes and high- rise urban districts. A high load density means a less extensive distribution system, which is very expensive. Shorter runs also minimize thermal and pressure losses and maintenance costs. A desirable companion to high load density is a favorable load factor. Means that the aggregate load over time tends to approach the peak block load condition.This analysis considers both factors, olibanum making DCP a amend option.Infra mental synthesis RequirementsDistrict Cooling evasion needs a central plant and a central pipeline network to function. Consideration of these site necessities for district cooling facilities in be after and programming process for Strategic New Development areas in the beginning stage is priority to hold the master plans and certain easy work of District Cooling intent. (Parsons 2003) Due to fast paced reflection process any changes to the master plans and infrastructure corridors, can severely impact the completion of the district cooling project.Traffic Impact ReviewSince some of the pipelines laying works need to be on busy roads it is important to have an extensive Traffic Impact legal opinion. For Dubai health care city careful notification was provided to the stakeholders to guarantee no inconvenience was caused due to pipeline installation. infra Ground CongestionThese are higher than anticipated costs since there may be unexpected costs relating to congestion in c worldly concernes tine services. These need to be overcome primarily in the planning process. (IDEA 2007)Chilled Water Temperature DifferentialLow chilled water temperature differential ( T) is a major district cooling weakness. Poor T performance at cooling coils means lost cooling capacity, wasted energy, extra cost and added complexity for a thermal utility, its chilled water customers, or both. Health care city district cooling plant has power consumption of 1.12 kw/tr which is more than the want consumption of less than 1 kw/tr due to low chilled water temperature difference. This increases operating costs. To encourage customers to invest in technology to improve T performance in their buildings, an increasing number of utilities have established chilled water rates that vary inversely with T . Figure 4.4 is an example of rates charged to customers from one prominent university in the United States. As can be seen, the lower the T, the greater the rate. Conversely, customers that minimize their flow rate per ton cooling are rewarded. (Moe 2005)Risks and Uncertainties Faced By District Cooling CustomersThere is no bargaining power with the District Cooling Services supplier once a building is connected to District Cooling Scheme and Uncertainties over future tariffs.Risks and Uncertainties Faced By District Cooling Investors pauperism is unpredictable, Uncertainty in dealing with building owners on District Cooling Supply Agreement (negotiations can be time consuming), Unpredictability relating to land costs for District Cooling plant room and distribution pipelines and High initial capital investments with long payback periods. (Parsons 2003)Strategic Environmental AssessmentNoiseThe central chiller plant and pumps of the district cooling intention are crime syndicated in underground plant rooms, this reduces the noise. As buildings connecting to District Cooling Scheme do not need to have their own chiller plant, the district cooling user building will have no no ise. Appropriate techniques can be implemented to reduce the noise during construction stage of district cooling scheme. (Parsons 2003)Air QualityDistrict cooling reduces electricity energy thus minimising coulomb dioxide emission and will serve improve air quality. Based on the case study for 4800 hours of operation the energy saving by using district cooling would be (1.91 -1.12)kw/ton x 4800 hrs x 18000 tons i.e. 68,256,000 KWh , which is equivalent to 104,772,960 lbs of CO2 (Electricity carbon emission factor 1.535 lbs CO2/KWh).(EPA 2006)Benefits of district cooling for project ownersA highly efficient solution Given that this region has extreme heat, air conditioning can account for as much as 70% of the energy consumption in a typical building. Moving this load from individual houses to a central plant, the housing electric load is reduced considerably and along with it the number of electric substations and length and sizes of electric cables. District cooling requires far less electric power than multiple plant rooms or ducted splits. Also the plant room can house the electric substation, enormously reducing the electric works.Significant capital and O M cost reductionRemoving in-building or on-premise chiller plants by using district cooling schemes means that availability of free land for other use. Also project owners do not need to buy more land to operate and maintain complex central air conditioning plants. They also need not have to replace expensive equipment. The industry has a two part tariff structure which is complex to understand. It is based on an Annual Capacity or Connection Charge for every ton committed to a property and also a manipulation Charge for the energy used measured through an energy meter installed for every end user. Palm district cooling has developed a new form of tariff structure that maintains the consumption charge but replaces the annual capacity charge or connection charge with a One Time Service Connection Cha rge (AED/sq ft) of the property. (Prashant 2007)Benefits of this tariff structureDeveloper need not pay advance cost for DC, Developer does not need to pay for any air-conditioning chiller units during construction stage. The tenant or property owner contributes to the cost of the DC system at the time of buy his property as he would do with conventional AC equipment. When district cooling is an option, the building owner can invest capital towards amenities for tenants. reduce project complexity means faster project completion sanctified experienced professionals take over the complex task of providing the cooling needs of the project, simplifying and expediting the project development cycle and expediting move-in dates and income generationImproved ROI numbers lessen initial up-front capital outlays for developers, faster move-in dates, reduced OM costs and the elimination of costs related to technical staff all translate into less fiscal risk for project owners, with improved re turn on investment and better project economies overall for developers and owners.No idle expensive capacityDistrict Cooling Solutions allow project owners to buy the capacity they need when they need it.Improved reliability and ease of operationEconomies of scale allow for cultivate redundant systems resulting in superior 100% up-time performance and ease of operation for project owners. Units used are high-tech and industrial which dramatically decreases the failure frequency compared to commercial equipment. District cooling reliability is in lavishness of 99.94%. (Source IDEA). (Papadopoulos et al 2006) The central chiller plant concept, almost by definition, is more flexible and more reliable and possesses a greater degree of diffuseness than the concept involving individual cooling packages.Greater flexibility in designArchitects have more creative leeway due to the elimination of heavy machinery.Ecologically friendlyIt provides for a noise free, clean environment for the t enants. The absence of tall towers allows for a clean environment.