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

Mon Oct 22 07:53:27 PDT 2012

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
>>>>> _______________________________________________
>>>>> TRNSYS-users mailing list
>>>>> TRNSYS-users at 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 at 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 at tess-inc.com

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

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