# lecture objectives: finish heat pump example review psychrometrics swimming pool example

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• Slide 1
• Lecture Objectives: Finish heat pump example Review Psychrometrics Swimming pool example
• Slide 2
• Heat pump example Heat Pump Consumes heat energy Rejects heat energy A recreation center Ice Rink Swimming pool Electric power for a compressor EvaporatorCondenser 85-89 o F 30 o F
• Slide 3
• Ice Rinks Energy flow
• Slide 4
• Challenges for this problem Circulating fluid Adjustment of evaporation and condensation temperatures Adjustment of capacity for design condition Control of capacity for non design conditions Need to study load profiles Design sophisticated control Provide backup system
• Slide 5
• Psychrometrics (Swimming pool example)
• Slide 6
• Psychrometric Chart Need two quantities for a state point Can get all other quantities from a state point Can do all calculations without a chart Often require iteration Many digital psychrometric charts available Can make your own Best source is ASHRAE fundamentals (Chapter 6) Or electronic version at: http://www.handsdownsoftware.com/
• Slide 7
• Slide 8
• Connection between W and Pw (W humidity ratio Pw water partial pressure) PV = mRT (Ideal Gas Law ) P = P w + P a R = gas constant P = pressure V = volume T = absolute temperature W = humidity ratio Subscripts: w is water vapor, a is dry air
• Slide 9
• Swimming pool energy and mass balance
• Slide 10
• Evaporation Heat loss by evaporation: pool W s W T air T pool hmhm pool WsWs T pool W air Further analysis can be conducted in the psychrometric chart Depends on the air speed and even more on the condition of the water surface (people splashing in the water)
• Slide 11
• Process in AHUs Example AHUs for swimming pools MENERGA ThermoCond 19
• Slide 12
• Swimming pool heating
• Slide 13
• Dehumidification using outside air in Winter and Summer
• Slide 14
• More advance control MENERGA ThermoCond 29
• Slide 15
• Dehumidification using outside air in winter Condenser in the swimming pool Evaporator Condenser in the air stream Compressor of the heat pump
• Slide 16
• Recirculation of air with dehumidification catalog