PhD Thesis - Energy Systems Research Unit - University of Strathclyde

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or decrease the flow rate of the cooling water through the cooling coil. Based on theoperating times listed in Table 3.1 and Table 3.3 similar control schemes wereimposed on the other heating and cooling coils.For the 6 household building plant system a similar scheme shown in Table 3.6 wasused.Table 3.6 - Control scheme used to control the plant in the 6 household buildingControl Loop 1DescriptionTime – basedcontrol schemeControl Loop 2DescriptionTime – basedcontrol schemeControl Loop 3DescriptionTime – basedcontrol schemeControl Loop 4DescriptionTime – basedcontrol schemeControl Loop 5CHP controlControl scheme used to control (actuate) CHP. Control is based on feedbackreceived from temperature sensor sensing the temperature of the water return tothe hot water storage tank.00.00-24.00 Hours 65°C / 75°C ‘On’/‘Off’ Control with 10ºC dead bandAuxiliary boiler controlControl scheme used to control (actuate) auxiliary boiler. Control is based onfeedback received from temperature sensor sensing the temperature of the waterflowing through hot water pump 1.00.00-24.00 Hours 60°C / 65°C ‘On’/‘Off’ Control with 5ºC dead bandBypass valve calorifier controlControl scheme used to control the amount of hot water passing through orbypassing calorifier. Based on a proportional control which senses thetemperature of the water flowing through the DHW supply pump the valvevaries between fully open (F.O) and fully closed (F.C.).00.00-24.00 HoursChillerFully Open 65°CFully Closed 60°CProportional ControlControl scheme used to control (actuate) chiller. Control is based on feedbackreceived from temperature sensor sensing the temperature of the water returnfrom the cooling coils.00.00-10.00 Hours 12°C / 6°C ‘On’/‘Off’ Control with 6ºC dead band10.00-15.00 Hours - Chiller ‘Off’15.00-24.00 Hours 12°C / 6°C ‘On’/‘Off’ Control with 6ºC dead bandDHW pumpDescription Responds to external file created using DWH profile modelled in Chapter 2Control Loop 6DescriptionBypass valve cooling coil 1 controlControl scheme used to control the amount of chilled water passing through orbypassing cooling coil 1. Based on a proportional control which senses thetemperature of the air return from the ground floor apartment the valve variesbetween fully open (F.O) and fully closed (F.C.).102
Time – basedcontrol scheme00.00-08.00 Hours Valve varies between fully open and fully closed whenair temperature varies between 24ºC-21ºC respectively.08.00-15.00 Hours No control15.00-24.00 Hours Valve varies between fully open and fully closed whenair temperature varies between 24ºC-21ºC respectively.In general, the control scheme used for the 6 household building is similar to thecontrol scheme used for the 3 household building, however the operating times of thecontrols actuating the chiller, the CHP and the bypass valves of the cooling andheating coils were adjusted to reflect the different operating periods imposed by thedifferent (time-sensitive) thermal demands of the 6 household building.3.3 The absorption chiller modelTo facilitate the dynamic modelling of trigeneration systems, a dedicated dynamicchiller model had to be developed for ESP-r. The chiller model described representsa single-effect hot water fed lithium bromide-water absorption chiller, the most apt[15] for use in CCHP trigeneration systems, however the same rationale can beextended to other chiller setups. The pragmatic, yet fully-dynamic model describedwas designed to be easily calibrated using data that can be obtained by measurementsof inflows and outflows to a chiller, without resorting to intrusive measurements,thus greatly reducing the complexities involved and simultaneously increasing themodel’s flexibility. The model described here builds upon the work done byBeausoleil-Morrison et al. [16] who developed a steady state chiller model for thetool.3.3.1 The absorption chiller cycleContrary to a vapour compression cycle which relies on an energy-intensive processof compressing the refrigerant vapour exiting the evaporator through the use of acompressor, an absorption refrigeration cycle relies on the affinity between twoliquids to dissolve the refrigerant inside a liquid solution which can then be pumped,in a less energy-intensive process. Figure 3.3 shows a schematic of a single-effect hotwater fed chiller showing the associated external (dashed lines) and internal (solidlines) flows inside the chiller. The external flows constitute the feed flows, that is,the hot, chilled and cooling water circuits, whilst the internal flow is the cycle103
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University of StrathclydeDepartment
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ACKNOWLEDGEMENTSIt has been a long
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ABSTRACTThe domestic sector account
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TABLE OF CONTENTSACKNOWLEDGEMENTSAB
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2.4.3.3 Aggregated loads frequency
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4.1.1.1 Factoring for electricity g
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5.5.1.2 Present worth assuming a va
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LIST OF FIGURESFig. 1.1 Separate ge
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Fig. 2.38 Aggregated DHW draw profi
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Fig. 5.23 PP for Scenarios 1 and 2
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uilding 95Table 3.5 Control scheme
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ACRONYMS & ABBREVATIONSBMS Building
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CHAPTER 1INTRODUCTIONChapter overvi
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uildings, and Directive 2006/32/EC
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Micro-cogeneration can make use of
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offer reasonable and adequate retur
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system in a residential building, i
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conditions have on the performance
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effective manner. The research in t
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investigate how a residential micro
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Table 1.1 also includes additional
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1.7 Chapter References[1] DG for En
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[18] Pehnt, M., Cames, M., Fischer,
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[39] Cardona, E. and Piacentino, A.
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[56] Shin, Y., Seo, J.A., Cho, H.C,
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2.1 Modelling residential demand -
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minute resolution data. The researc
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2.3.1 Example: specifying the build
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Table 2.1 - Dimensions of the model
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In this second enlarged building, t
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Table 2.3 - Main characteristics of
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Table 2.4 - Main characteristics of
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esolution demand data for individua
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the original data (see equation 2.1
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the course of a year. The end resul
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specific appliance at a particular
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consumption during this period is e
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Page 78 and 79: Table 2.7 - Scaling factors for the
Page 80 and 81: NVF values for washing machines, el
Page 82 and 83: Table 2.10 - Annual electrical ener
Page 84 and 85: 2.4.4 Creating the profiles used in
Page 86 and 87: Fig. 2.16 - Electrical demand profi
Page 88 and 89: Fig. 2.19 - High efficiency electri
Page 90 and 91: 2.4.4.3 6 Household buildingAs ment
Page 92 and 93: 2.29 and Figure 2.30 show the resul
Page 94 and 95: period [11].In order to improve on
Page 96 and 97: (as discussed by Richardson et al.
Page 98 and 99: similar fashion to the modelling of
Page 100 and 101: observed measurements from a number
Page 102 and 103: Fig. 2.37 - Total internal heat gai
Page 104 and 105: comparing water consumption related
Page 106 and 107: various aspects which make up the h
Page 108 and 109: natural Resources" - (LN 238 of 200
Page 110 and 111: in Domestic Appliances and Lighting
Page 112 and 113: [49] DEFRA (2010). "Dishwashers Gov
Page 114 and 115: CHAPTER 3MODELLINGMICRO-TRIGENERATI
Page 116 and 117: the same research also suggests tha
Page 118 and 119: cooling device in conjunction with
Page 120 and 121: simulation tool ESP-r by explaining
Page 122 and 123: Fig 3.2 - Basic micro-trigeneration
Page 124 and 125: 3.2.3 Control strategies for the pl
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Page 130 and 131: arbitrary cycle configuration, usin
Page 132 and 133: coefficients for the future and pre
Page 134 and 135: Applying basic energy and mass cons
Page 136 and 137: CH Power , the chiller’s refriger
Page 138 and 139: general form of equation (3.16) [33
Page 140 and 141: functions of hot water circuit inle
Page 142 and 143: circuit were obtained and how the p
Page 144 and 145: the internal high and low pressures
Page 146 and 147: the imaginary boundary constituting
Page 148 and 149: the model was then compared to a se
Page 150 and 151: Fig. 3.9 - Modelled chilled water c
Page 152 and 153: standard deviation was calculated t
Page 154 and 155: The selected tank size is based on
Page 156 and 157: 3.5 Summary of Chapter 3This chapte
Page 158 and 159: Conservation in Buildings and Commu
Page 160 and 161: uilding simulation." Doctoral Thesi
Page 162 and 163: CHAPTER 4SIMULATIONMETHODOLOGYANDAN
Page 164 and 165: Table 4.1 - Scenarios investigatedS
Page 166 and 167: The building fabric, building size
Page 168 and 169: analysis in the case of the interme
Page 170 and 171: micro-trigeneration system are thos
Page 172 and 173: profile for that same time period (
Page 174 and 175: 4.2.1.3 Calculating the fuel consum
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cogeneration technologies [16].- (4
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the present 1.088 kgCO 2 per kWh de
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Table 4.4 - Explanation of the cash
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FIT and considering the cost involv
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impact they have on the energetic,
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Conservation in Buildings and Commu
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CHAPTER 5RESULTSANDDISCUSSIONThis c
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increases so does energy-efficiency
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the building fabric is most effecti
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Instances where the load duration c
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households, GF refers to the ground
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Finally, and this will be the discu
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In the table, the low and high effi
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The scenario with the lowest number
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Comparing Figure 5.3 and 5.4, respe
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number of cycles during the cooling
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5.3.3 Chiller’s performanceAs dis
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5.3.4 Electrical performance of the
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decrease in net imports and net dem
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Table 5.10 - Micro-trigeneration sy
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trigeneration system primary energy
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Table 5.11 - Micro-trigeneration pr
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The PES obtained for the different
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Difference inprimary energybetween
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Similar results are obtained for al
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2 High/High efficiency3 High/Curren
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Fig. 5.8 - Sensitivity of Emissions
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Similarly to the effect on PE SEPAR
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5.5 Micro-trigeneration system econ
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As electricity costs increase (rela
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ii.In the latter case the magnitude
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Resultingdifference incash flowDiff
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Multiple of current electricity tar
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of the system diminishes with incre
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Fig. 5.17 - CF and CF component ter
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shows that exporting all the cogene
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LPG price level when the micro-trig
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Minimum threshold viability of the
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Similarly to the PW and the IRR, it
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Table 5.13 - Summary of micro-trige
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performance of the micro-trigenerat
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directly affect the system’s ener
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micro-trigeneration system. Convers
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CHAPTER 6CONCLUSION:OUTCOMESANDFUTU
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and power demands of the building.
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circuits associated with the absorp
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the subject. More work therefore ne
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plant models using the building sim
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APPENDIX AEquation factors for sele
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Factors for use in equation (2.1) f
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APPENDIX BElectrical demand profile
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Fig. B4 - Current efficiency electr
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Fig. B10 - High efficiency electric
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Fig. B16 - Current efficiency elect
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Component ESP-r Database: Annex 42
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0.0000 #88 Performance map: Thermal
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99.999 #1 Evaporator Total Mass (Fl
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100.00 #13 Boiling temperature of f
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One way to solve a partial differen
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The ‘self coupling term’ is def
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C ******************** CMP73C *****
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&COMMON/PCOND/CONVAR(MPCON,MCONVR),
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C and the inlet point into the solu
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IF(CSVF(INOD1,1).LE.BDATA(IPCOMP,17
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C Calculate T1 (DegC): T1 = ((T16-T
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XST=4010 DST=-(9.133128) + (0.94396
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& + 2500.559)*1000C Refrigerating p
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End IfC Calculate h3 (J/kg): h3=h2+
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&&ElseEnd IfActPow=0ActPow = PCONDR
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C Node 1, thermal mass effected by
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WRITE(ITU,*) ' Connection(s) ',ICON
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Fig. F.1 - IRR for scenarios with d
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Fig. F.5 - PP for scenarios with di
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PhD Thesis - Energy Systems Research Unit - University of Strathclyde

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