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Re: [TRNSYS-users] Temperature level control is not working

Michael,
  My apologies for the delay in looking at the problem. You have set up the temperature level control correctly (nicely done). There are two reasons why your zone is not holding temperature. First, the thermostat model is set to hold a cooling set point temperature in the kitchen of 24C. However, your cooling device is set to provide a 25C supply temperature. I would recommend a supply temperature in the neighborhood of 10-12C. Second, the zone that you are controlling (the kitchen) has a LOT of internal gains and the capacity of the cooling device that you have selected (10,000 kJ/h - 2.8kW) is not enough to cool the space.

  As a side note, there are a few problems with the way you've done the cooling. First, the specific heat of the working fluid has to be set to 1.007 kJ/kg.K as the device is cooling air, not water. Second, Type92 is really intended as a liquid cooling device. As such, it does not calculate the impact of humidity. You have started out correctly by passing a humidity variable around the cooling device and then reconnecting it at the outlet. However, you need to pass the absolute humidity ratio, not the relative humidity because relative humidity changes as soon as there is a change in dry bulb temperature, even if there is no change in moisture content. Pass the absolute humidity ratio from the fan to a Type33 psychrometrics routine. Pass the outlet temperature from the cooling device from the Type92 to the Type33. This isn't quite right either because in this case, you are assuming that there is no condensation of water out of the airstream as it is cooled. In almost all cases, there would be some condensation and as a result, some dehumidification of the air as it is cooled.

Best,
 David


On 10/30/2012 01:41, Michael Diekerhof wrote:
Dear all,

in my masterthesis I am trying to connect a heat pump (type401) to a buffer storage and then to type 56. But the first step was to change from energy rated control to temperature level control; so I followed the TRNSYS tutorial. But somehow the indoor air temperature (kitchen) is not controlled at all. I´ve checked it twice and as i can see i did everything exactly like the tutorial explained. As long as I am not able to control this temperature around 20°C I shouldn´t think about implementing a heat pump and a storage.

I attached the project and the bui.file and as you can see the heating is on and especially in the cold months (e.g. january) the room temperature is abnormaly high.

I am very thankful for any suggestion how to control the T_Air_Kitchen around 20°C ! I have no idea what could be wrong right now and at my university there´s no one who has experiences with TRNSYS. So thanks in advance!

Best,
Michael 


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