HVAC Loads output question

5 posts / 0 new
Last post

Hi,

I'm modeling a 1940s-era apartment building for a geothermal retrofit. The current heating system consists of hot-water radiators supplied by gas-fired boilers. Cooling is supplied by window air conditioning units in each apartment. The ultimate objective is to generate building space heating and cooling loads to size a heat pump and ground heat exchanger - by space heating and cooling loads, I mean the total heat which has to be added or removed by the HVAC system to maintain all conditioned spaces at their set points.

Currently I'm generating hourly loads from the Building HVAC hourly report block using variables 1 & 2, entitled "Building cool load (coils + losses&gains)" and "Building heat load (coils + losses&gains)". Are these the right variables to use, or do I need to look somewhere else?

Thanks,

Drew Morrison

amorrison's picture
Offline
Joined: 2011-01-27
Reputation: 0

Drew,

I typically use the "LS-B Peak Load Components" report from the sim-output
file for loads.

Brian Gregory's picture
Offline
Joined: 2011-09-30
Reputation: 0

Brian,

Thanks for that input. I have a follow-up question: I looked at the LS-B report and it has a note that says "The above loads are calculated assuming a constant indoor space temperature." Is this temperature equal to the setpoint temperature of the space?

Also, is there a counterpart to this report that outputs hourly values?

Thanks
Drew

amorrison's picture
Offline
Joined: 2011-01-27
Reputation: 0

It is my understanding that the loads are calculated based on the "Indoor
Design Temperature" and not the setpoint temperature. You can generate
hourly reports using the "Space" blocks in the hourly report blocks however
you would need to make a separate block for each space.

Brian Gregory's picture
Offline
Joined: 2011-09-30
Reputation: 0

Is there any way to find loads based on the setpoint temperature, not on the design temperature?

Or - if I made the design temperature equal to the setpoint temperature, would the loads change correspondingly?

amorrison's picture
Offline
Joined: 2011-01-27
Reputation: 0