How do I simulate temperatures in a naturally ventilated greenhouse, and potential heat transfer to connected building?
I'm looking to model a rooftop greenhouse on top of a 3 storey hotel building. We are wanting to look at the value of using excess heat from the greenhouse to heat spaces in the building below. The greenhouse will be naturally ventilated and unheated. I've been attempting to model the temperature inside the greenhouse using energyplus (editing a .idf file exported from Sefaira) but it's been giving some pretty odd results. I have a feeling my issue may be in allowing for natural ventilation. The way I currently have it modelled the internal temperature in summer seems reasonable, peaking out at about 37-40 deg C depending on U-value of the glass, however in winter the internal temperature in the greenhouse drops below the outside temperature at some points which I would have thought impossible? I'm using "Zone Mean Air Temperature" as the temperature output variable.
For the natural ventilation setup I have the venting availability set to 1 constantly, the ventilation temperature setpoint set to 22.5 deg C constantly, and the temperature difference for maximum and minimum venting open factor set to 5 and 0.5 respectively. Does this seem right?
Secondly, does anyone know how I might be able to model the reduction in heating that could be achieved by using excess heat from the greenhouse to heat spaces below?
Thanks!
