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Re: [TRNSYS-users] Heat Pump mass flow rates (e.g. Type 401)



David,
I exactly followed the tutorial. Thanks for that. But unfortunetaly I can´t see a controlled roomtemperature!! Also in the already existing example "HVAC-Building" that is using Type108, I cant see a controlled roomtemperature (20°C). Where´s the mistake since i haven´t changed anything in the example? When I was plotting the the Indoor temperature TaBack, I was expecting a almost constant temperature but not a temperature fluctuating between -8 and 8°C.
Best,
Michael





Am 22.10.2012 23:15, schrieb David BRADLEY:
Michael,
  well fundamentally, a furnace heats air and I think the heat pump you were talking about heats water that then goes to a radiator, correct? If so, then the furnace would be connected to Type56 by means of a VENTILATION type in TRNBuild/Type56.
Best,
 David



On 10/22/2012 10:09, Michael Diekerhof wrote:
David,
thanks a lot. I´ll try to figure that out. Just a short question before starting: In case I dont use a storage, the type 121a (Furnace) will be replaced with my heat pump type, right ?? If I use a storage tank, this one  will replace my type121, won´t it ?
Michael


Am 22.10.2012 16:53, schrieb David BRADLEY:
Michael,
  The HEATING and COOLING types that are built into TRNBuild and Type56 are primarily used for computing the idealized heating and cooling loads of the space. Those loads can then be imposed on a system but the performance of the system is then dependent only on that load, not on the delivery temperature or the room temperature. This method of calculating system energy use is called Energy Rate Control. What you are aiming for in your simulation is something called Temperature Level Control where a themostat senses room temperatures and sends control signals to equipment. The equipment provides flows of hot or cold water and air to the delivery devices and the room temperatures react accordingly. The Type56 model is computing an energy balance on the space that reacts to the delivery devices. You need to get away from using the built-in idealized HEATING inputs and towards defining the ventilation streams, active layers, and energy gains that will cause the space temperature to go up or down. There is a tutorial available that will step you through the basic process of migrating from Energy Rate Control to Temperature Level Control. Even though it does not directly apply to your radiator system, I think it will help your understanding of the underlying concepts.

http://sel.me.wisc.edu/trnsys/downloads/tutorials_and_examples/tlc_tutorial17.pdf

Best,
 David



On 10/20/2012 08:43, Michael Diekerhof wrote:
David,
Unfortunetaly I don´t have access to the TESS library. I´m sorry but I dont understand what you were meaning with: "If you do not, then I would imagine that you might be able to come up with a simplified set of equations that would give you the gains to the space that you need. "

Do you mean that I use the GAINS to adjust the radiative and convective part ? But how to take the room temperature into account by also considering the outlet temperature out of my storage ?? Isn´t there also a way to work with HEATING INPUTS ?! I still dont have an idea how to cover my heat demand by using the outlet temperature :(

Best,
Michael




Am 19.10.2012 20:15, schrieb David BRADLEY:
Michael,
  Ideally, you need a radiator model that will deal with the water side, take room temperature from Type56 and output the convective and radiative gains to the space as outputs. Such a model exists in the TESS HVAC library for Trnsys17 if you have access to it (Type1231). If you do not, then I would imagine that you might be able to come up with a simplified set of equations that would give you the gains to the space that you need.
Best,
 David


On 10/18/2012 09:24, Michael Diekerhof wrote:
David,

thanks a lot. I´ll have a look.

Could you please help me in another case. My plan is to connect the HP to a storage tank and then giving a temperature from the storage (type4) to my type56... How can I realize that my type 56 can be heated to achieve a constant room temperature of e.g. 20°C ?!

Someone told me that I must use HEATING and then INPUT...  but what if i would like to simulate a simple radiator with a simple inlet temperature of e.g. 55°C.

Do you understand my problem? I dont know how to cover my heat demand out of the storage.

Thanks in advance

Best,
Michael



Am 18.10.2012 16:16, schrieb David BRADLEY:
Michael,
  I would recommend that you look online at manufacturer's sites for similarly sized heat pumps. Trane and Carrier both have significant amounts of performance data in the product literature parts of their sites. You can probably get a good estimate of the flow rates on both the condenser and evaporator sizes from them.
Best,
 david


On 10/18/2012 03:53, Michael Diekerhof wrote:
Dear all,

I´m working with the heat pump non-standard type 401 and try to display an air-source heat pump.

I dont have typical values for the Input 2 (evaporator mass flowrate) and Input 4 (condenser mass flowrate).
The only real connection I´m using is the dry bulb temp, coming from type 15, as the evaporator inlet temperature. For the massflowrates I would like to assume constant values.

How can I adjust an outlet condenser temperature of e.g. 55°C. Just about the massflowrates ?!

Does anyone have experience with heat pump mass flow rates?! I guess it´s not necessary to have expieriences with Type 401.

I´m thankful for any advices.

Best,

Michael
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TRNSYS-users@cae.wisc.edu
https://mailman.cae.wisc.edu/listinfo/trnsys-users





Am 18.10.2012 16:16, schrieb David BRADLEY:
Michael,
  I would recommend that you look online at manufacturer's sites for similarly sized heat pumps. Trane and Carrier both have significant amounts of performance data in the product literature parts of their sites. You can probably get a good estimate of the flow rates on both the condenser and evaporator sizes from them.
Best,
 david


On 10/18/2012 03:53, Michael Diekerhof wrote:
Dear all,

I´m working with the heat pump non-standard type 401 and try to display an air-source heat pump.

I dont have typical values for the Input 2 (evaporator mass flowrate) and Input 4 (condenser mass flowrate).
The only real connection I´m using is the dry bulb temp, coming from type 15, as the evaporator inlet temperature. For the massflowrates I would like to assume constant values.

How can I adjust an outlet condenser temperature of e.g. 55°C. Just about the massflowrates ?!

Does anyone have experience with heat pump mass flow rates?! I guess it´s not necessary to have expieriences with Type 401.

I´m thankful for any advices.

Best,

Michael
_______________________________________________
TRNSYS-users mailing list
TRNSYS-users@cae.wisc.edu
https://mailman.cae.wisc.edu/listinfo/trnsys-users






-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley@tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com


-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley@tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com