Dear all users,
About the Type 941 (Trnsys v.17):
- First: can you confirm if I understand its functioning? I use it only for heating, at the moment.
- Second: I believe that the values of the COP it isn’t correct, or I don’t understand it. The COP trend depends on the external files with the heating performance data, is it? In this file I have:
Capacity increases when the entered water temperature decreases and the air temperature increases ( <Tin,w and >Tin,a → >Capacity)
Power increases when the entered water temperature increases and the air temperature decreases ( >Tin,w and <Tin,a → >Power)
So the COP increases when the entered water temperature decreases and the air temperature increases ( <Tin,w and >Tin,a → >COP). But the simulation gives opposites results.
The external files are wrong? or I misunderstand the Type functioning?
I tried to calculate the COP with excel and the results come out as per the provision, therefore different from TRNSYS' results.
About the first question:
I know as Parameters:
- Specific Heat of Liquid Stream
- Blower Power (pb)
- Total Air Flowrate (Fa,d)
- Rated Heating Capacity (qh,d)
- Rated Heating Power (ph,d)
and as Input:
- Inlet Liquid Temperature (Tin,w)
- Inlet Liquid Flowrate (Fin,w)
- Inlet Air Temperature (Tin,a)
- Inlet Air Humidity Ratio
- Inlet Air % Relative Humidity
- Heating Control Signal
and as external files
- Heating and cooling catalog data for the capacity and power as a function of entering the water and air temperature (fc=f(Tin,a;Tin,w) and fp=f(Tin,a;Tin,w))
So when the simulation running:
- The Type 941 reads the air and water entering temperature (Tin,w and Tin,a)
- Interpolates the heating performance file and multiplies this “performance factor” by HP Rated capacity and power. (fc(Tin,a;Tin,w) and fp(Tin,a;Tin,w))
- So obtain Capacity and Power as a function of entering the water and air temperature by each time step. (qh(t)=fcqh,d and ph(t)=fpph,d)
- Calculates the COPh as a ratio between qh(t)/(ph(t)+pblower) , i put paux=0
Is it correct??
Thank you in advance,
Regards,
Miriam Di Matteo