PhD Thesis - Energy Systems Research Unit - University of Strathclyde

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functions of hot water circuit inlet temperatures;Stage 2 - An expression for the chiller’s refrigerating power output is derivedas a function of all of the water circuit inlet temperatures; andStage 3 - The thermal capacities of the chiller model constituents areidentified.The data required to calibrate the chiller (see Table 3.8) is derived from two sources:Some of the parameters such as the highest and lowest permissible high andlow pressure, the minimum chilled water protection temperature and theworking minimum hot water outlet temperature can be extracted directlyfrom manufacturer’s data sheets as these are typically listed to avoid anydamage being caused to the chiller. The high (p high ) and low (p low ) pressure curve coefficients (a 0 , a 1 , b 0 and b 1 ),the chiller’s refrigerating power output function (CH Power ) curve coefficients(d 0 , d 1 , d 2 and d 3 ), the thermal masses (M i , M j and M g ) and the mass weightedaverage specific heat values ( , and ) all require empirical data, obtainedfrom a three stage calibration process. Details on how these values can beobtained are given in Sections 3.3.5.1, 3.3.5.2 and 3.3.5.3.Table 3.8 lists the parameters that require calibration together with the respectivevalues obtained after calibrating the model with experimentally measured dataacquired for a 10 kW th absorption chiller developed by SK SonnenKlima GmbH [36,37]. The chiller is adequately sized to cater for a broad spectrum of residentialthermal loads.For the nodal parameters, alternative values obtained from a more pragmaticcalibration process are shown and compared to measured values later.116
Table 3.8 - Component coefficients and data making up the absorption chillerNodal parameters:Node iValue1 M i - Evaporator total mass (kg) 47.0002 - Mass weighted average specific heat of evaporator (kJ/kgK) 1.7180Node j3 M j - Condenser and absorber total mass (kg) 122.404 - Mass weighted average specific heat of condenser and absorber (kJ/kgK) 1.7670Node g5 M g - Generator total mass (kg) 79.7006 - Mass weighted average specific heat of generator (kJ/kgK) 1.8070Whole device parameters:1 Recovery heat exchanger efficiency (ƞ) 0.64002 UA Modulus (W/K) 3.50003 p High - High pressure curve coefficient (a 0 ) 0.07354 p High - High pressure curve coefficient (a 1 ) 0.34295 Highest permissible high pressure (kPa) 8.00006 Lowest permissible high pressure (kPa) 4.00007 p low - Low pressure curve coefficient (b 0 ) -0.01378 p low - Low pressure curve coefficient (b 1 ) 2.40199 Highest permissible low pressure (kPa) 2.000010 Lowest permissible low pressure (kPa) 1.000011 Working maximum outlet temp cooling water (ºC) 40.00012 Working minimum outlet temp hot water (ºC) 42.00013 CH Power - Power function coefficient (d 0 ) -6370.014 CH Power - Power function coefficient (d 1 ) 304.9015 CH Power - Power function coefficient (d 2 ) 168.3016 CH Power - Power function coefficient (d 3 ) -76.52017 Minimum chilled water temp protection (ºC) 2.500018 Circulation pump electrical efficiency (-) 0.9000Control variables:1 ON/OFF control signal (-) 1/03.3.5.1 Calibration stage 1: Obtaining the cycle high and low pressures in terms ofthe hot water circuit inlet temperatureThis section explains how the general relationships between the internal high (p high )and low (p low ) cycle pressures and the incoming inlet temperature of the hot water117
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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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awarded on a random basis following
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Table 2.7 - Scaling factors for the
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NVF values for washing machines, el
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Table 2.10 - Annual electrical ener
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2.4.4 Creating the profiles used in
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Fig. 2.16 - Electrical demand profi
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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
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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
Page 126 and 127: or decrease the flow rate of the co
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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 142 and 143: circuit were obtained and how the p
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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
Page 176 and 177: cogeneration technologies [16].- (4
Page 178 and 179: the present 1.088 kgCO 2 per kWh de
Page 180 and 181: Table 4.4 - Explanation of the cash
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Page 184 and 185: impact they have on the energetic,
Page 186 and 187: Conservation in Buildings and Commu
Page 188 and 189: 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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