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Re: [TRNSYS-users] Measured heat loads and air-water heat pump control

Dear Zhe,
  In addition to Jean Marais' response, I thought that I would mention that if you have precalculated loads, you can impose them either on an air stream or on a water stream using components from the TESS Loads and Structures Libraries (Type682 and 693). Jean is quite correct that it is best to have the weather data for the same year for which the loads were generated since the heat pump performance depends on ambient conditions.

  As for the second part of your question. There are two ways of modeling buildings and systems. The first way is that you calculate the loads and then impose them on the HVAC equipment. When you do this, however, you presuppose the zone temperatures. You no longer have any control over when the heat pump turns on and when it turns off. If there is a load (whether heating or cooling) it must be imposed on the heat pump. All of the control algorithms are built in to determining the space load.

  The other way of modeling a building is to allow the building temperature to float, to define a thermostat model that senses the room temperature and which is then used to command equipment to turn on and off to keep the space at its temperature. In this case there is no load. The conditioned air or water stream from the heat pump is delivered to the zone by whatever means are appropriate (a VENTILATION type in Type56, an active layer in Type56, a fan coil model, the heat pump itself...) and the zone temperature responds accordingly. The thermostat senses the room temperature change and decides whether to keep the equipment on or turn it off.
Kind regards,
 david



On 7/2/2012 07:00, Zhe Li wrote:

Dear all,

 

I am having two problems.

 

I have a measured hourly domestic heat loads for a year, I would like to implement it in TRNSYS simulation. Which component is best for this application? And how to actually implement it?

 

Also, I would like to utilise air-water heat pump.  However, I want to turn the heating mode on only, and completely turn off the cooling mode. How could I achieve this?

I would like to set room temperature at 22oC. I would want to turn on the heat pump at temperature below 20oC and turn it off when room temperature arrives at 24oC. I notice there are a few controllers are capable to do this, however, which one is the easiest in controlling this function?

 

Thank you very much in advance.

 

Zhe Li



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