Energy consumption for heating too low
I modeled a office building in Rome-Italy, ashrae climate zone 4A. Window-wall ratio is 22% with a good performance envelope in terms of tramittance. HVAC is composed of a reversible Heatpump/chiller air-to-water (COP and EER around 3.0) and fancoils, with natural ventilation, which i assumed about 0.3 airchanges/hour. Annual consumption for cooling is 28000 kWH, while heating, accounted in water system - other (i used waterheater:mixed+waterheater:heatpump) is 1500 kWh. UnmetSetpoint hours are below 50 hours. Moreover in the PEAK ENERGY END-USE - ELECTRICITY table, values for heating and cooling are similar: with maximum respectively of 25.3 kW (which and 22.2 kW C:\fakepath\Cattura.JPG C:\fakepath\Cattura2.JPG The second screenshot is from resultviewer and shows how the heatpump coil and the chiller power are not so different.
Comments
Some more information please - what is the size of the building? what are you assuming for thermostat temperatures? what specific HVAC objects did you use to model heating - what are their COPs in the model? What operational schedule does your HVAC follow? Do you have heat recovery?
Total building area is 810 m2 (8700 ft2); winter thermostat settings are 20°C (68°F), summer is 26°C (78.8°C), both considering 8 hour/day schedule. Heating system is composed by: waterheater:heatpump:pumpedcondenser with Coil:WaterHeating:AirToWaterHeatPump:Pumped which is 55,7kW-COP 3.3; i don't have any heat recovery.
I found out something interesting that may help resolving my issue:
1_Cooling coil total cooling energy of the coil:waterheating:airtowaterheatpumo:pumped doesn't work properly: it turns on just the first hour of the setpoint schedule, like a peak . Plant Supply Side Inlet and Outlet Temperature are identical (around 38°C) except at the time of the coil's peak, when inlet is 38°C and outet is 42°C.
2_Fancoils operation is normal in terms of schedule and rate
Any suggestion?