- Joined
- Dec 28, 2004
- Location
- Canada, BC, Gibsons
Well after assessing my needs I have determined the min/max deltas for the water inside to achieve a 21 - 25C room temp, I figure a 30C delta should be enough. To achieve this with good convection air flow. My water has to be from 50 to 70C. After determining the needed condensing temps, I searched for refrigerants with favourable pressure ranges and this is the list I compiled so far What you guys think?
R134a NBP: -26.1C; Ct:101.1C; Cp:589psi; BTU/Lb:1,806
R152a NBP: -24.0C; Ct:113.3C; Cp:656psi; BTU/Lb:7,481
R401a NBT: -34.4C; Ct:105.3C; Cp:669psi; BTU/Lb:- ---
Least ideal far as Ct and Cp go
R022- NBP: -40.8C; Ct:096.2C; Cp:600psi; BTU/Lb:0,946
R290- NBP: -42.2c; Ct:096.7C; Cp:616psi; BTU/Lb:21,625
Ct = Critical Temperature
Cp = Critical Pressure
NBP = Normal Boiling Point
R-152a so far looks like it will have the lowest head pressures at a condensing temp rang from 50-70C being its Ct is 113.3C and it has good moving capacity per Lb.
Max evap temp will be closely tied to the ambient air temps, the absolute min here in BC will be -10 and rarely at that, average is -05C for middle of winter So again its evap pressure looks to be favourable for the average winter temps. Only concern is I only have access currently to R-12 and R-22 TXVs, I suspect they should work after the necessary super heat corrections are made to the TXV providing they are at all needed!
Part specs SI & IP:
Air source evap/Condenser: 7.034Kw/H (2Ton)
Water source Evap/Condenser: 5.28Kw/H (1.5Ton)
Compressor: 4.98Kw/H (1.42Ton)
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Target room temp: 25C (77F) max ,((Heating mode))
Target water temp for heating mode 50C (122F) - 60C (140F) realistic?
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Temp range on the air source Cond/evap -10C (14F)max to a max of 40C (104F) I think it best to use some thing to ensure sufficient super heat during heating mode for when the weather gets warmer, to ensure it stays within range for cooling the compressor, like using a PWM that slows the fan as super heat goes up.
Part Numbers & Specs Misc:
- V46AC-1C Head pressure modulated, flow control valve (3/4 NPT)
- Red Hat 3/4 NPT Solenoid shut off valve (Low pressur drop)
- RainFresh FC100 5micron Filter (3/4 NPT)
- Temprite 340 series Oil sep 1/4 ODS
- CO-082 Sporlan catch all F/D SAE Flare
Apartment chararistics:
Window surface area total: 285.75 M^2 (937.5 F^2)
Floor Surface area total--: 214.27M^2 (703 F^2)
Air Volume total----------: 1,714.195M^3 (5,624F^3)
Room Width: 5.79M (19')
Room Length: 11.28M (37')
Room Hieght: 2.44M (8')
Room wall thickness: .127M (5") R-20
Design Temp: -10C (14F)
Windows are all single pain with wooden framing and no sealing, Walls have a Delta of 13.4C (56F) between inside & out side. Roof is R-50 about 2 feet thick.
So with that I estimate heat loss for the whole place + 25% to be 1.75Kw/pH (5,958.4 BTU/pH) Using the formula: U * A^2 * Dt(F) = BTU/pH
That is of course a ruftimate of general heat loss.
R134a NBP: -26.1C; Ct:101.1C; Cp:589psi; BTU/Lb:1,806
R152a NBP: -24.0C; Ct:113.3C; Cp:656psi; BTU/Lb:7,481
R401a NBT: -34.4C; Ct:105.3C; Cp:669psi; BTU/Lb:- ---
Least ideal far as Ct and Cp go
R022- NBP: -40.8C; Ct:096.2C; Cp:600psi; BTU/Lb:0,946
R290- NBP: -42.2c; Ct:096.7C; Cp:616psi; BTU/Lb:21,625
Ct = Critical Temperature
Cp = Critical Pressure
NBP = Normal Boiling Point
R-152a so far looks like it will have the lowest head pressures at a condensing temp rang from 50-70C being its Ct is 113.3C and it has good moving capacity per Lb.
Max evap temp will be closely tied to the ambient air temps, the absolute min here in BC will be -10 and rarely at that, average is -05C for middle of winter So again its evap pressure looks to be favourable for the average winter temps. Only concern is I only have access currently to R-12 and R-22 TXVs, I suspect they should work after the necessary super heat corrections are made to the TXV providing they are at all needed!
Part specs SI & IP:
Air source evap/Condenser: 7.034Kw/H (2Ton)
Water source Evap/Condenser: 5.28Kw/H (1.5Ton)
Compressor: 4.98Kw/H (1.42Ton)
----------------------------------------------------------------------------------------------
Target room temp: 25C (77F) max ,((Heating mode))
Target water temp for heating mode 50C (122F) - 60C (140F) realistic?
----------------------------------------------------------------------------------------------
Temp range on the air source Cond/evap -10C (14F)max to a max of 40C (104F) I think it best to use some thing to ensure sufficient super heat during heating mode for when the weather gets warmer, to ensure it stays within range for cooling the compressor, like using a PWM that slows the fan as super heat goes up.
Part Numbers & Specs Misc:
- V46AC-1C Head pressure modulated, flow control valve (3/4 NPT)
- Red Hat 3/4 NPT Solenoid shut off valve (Low pressur drop)
- RainFresh FC100 5micron Filter (3/4 NPT)
- Temprite 340 series Oil sep 1/4 ODS
- CO-082 Sporlan catch all F/D SAE Flare
Apartment chararistics:
Window surface area total: 285.75 M^2 (937.5 F^2)
Floor Surface area total--: 214.27M^2 (703 F^2)
Air Volume total----------: 1,714.195M^3 (5,624F^3)
Room Width: 5.79M (19')
Room Length: 11.28M (37')
Room Hieght: 2.44M (8')
Room wall thickness: .127M (5") R-20
Design Temp: -10C (14F)
Windows are all single pain with wooden framing and no sealing, Walls have a Delta of 13.4C (56F) between inside & out side. Roof is R-50 about 2 feet thick.
So with that I estimate heat loss for the whole place + 25% to be 1.75Kw/pH (5,958.4 BTU/pH) Using the formula: U * A^2 * Dt(F) = BTU/pH
That is of course a ruftimate of general heat loss.
