High pressure of R407C gas

[ENERGY-MW]

Hi, it seams I have some kind of problem with my heat pump prototype gas pressure. Gas pressure is 30bar when heating return 50'C, supply 56'C. Accordingly compressor is forced to work in high pressure mode with reduced COP.

Primary loop - ground horizontal loop, inlet temperature +12'C, outlet + 7'C
Secondary loop - at hot water (at summer) supply 56'C, return 50'C.
Compressor - copeland ZH45K4E.

Probably to much gas in cicuit?
Probably not correct adjustement of thermostatic valve?

I checked pirimary and secondary circuits, no dirt in filters, no air in system.

I would be glad to have some new ideas.

[taz24]

Hi, it seams I have some kind of problem with my heat pump prototype gas pressure. Gas pressure is 30bar when heating return 50'C, supply 56'C. Accordingly compressor is forced to work in high pressure mode with reduced COP.

Primary loop - ground horizontal loop, inlet temperature +12'C, outlet + 7'C
Secondary loop - at hot water (at summer) supply 56'C, return 50'C.
Compressor - copeland ZH45K4E.

Probably to much gas in cicuit?
Probably not correct adjustement of thermostatic valve?

I checked pirimary and secondary circuits, no dirt in filters, no air in system.

I would be glad to have some new ideas.

Why do you think you have a problem?

Discharge pressure at 30bar = 70 degC so if you are suplying water at 56degC the 30bar seems reasonable??

So what is your problem?

All the best

taz

.

[sedgy]

hi energy, < no pun intended< on my comperitor , on R 407C, 60C= 28 BAR and thats the maximum on its scale. you say , there is no air in the system , any ofn ? did you vac the system out yourself?
please let us know the outcome , sedgy

[taz24]

.

30bar is quite high and 70degC is hot.

Why do you want it that hot?
Underfloor heating need only be about 35degC delivery.

Best part of 60degC is for a radiator system and that high temp will
reduce you COP considerably

taz

.

[AlexG]

You said this is prototype. Did you calculate your condensor correct? Or check your subcooling. It must be 5...8K. Or maybe Sedgy is right, some air is in your refrigerant circuit...
And one more. Your 30 bar looks like R410A, not R407C. Are you sure you charged your system with proper *****?

[ENERGY-MW]

Hi, compressor is only for R407C, yes, I am sure gas ir correct.

[ENERGY-MW]

It's for DHW application and legionella protection, in heatinf season at -30'C outside, supply 45'C was enought.

[ENERGY-MW]

Vac of system and gas filling was done by one HVAC company. During testing I blowed of some amount of gas, probably gas composition is changed and it causes a problem? Probably I need to vac again and refill one more time.

[sedgy]

hi energy, but WHY you blow gas off?

[COBRAKAI]

How much gas did you blow off!! I would advise on a reclaim and also pressure test just to be sure. Then a recommission. I have seen some strange things when systems have been operating on R407 either composition has changed or noncondensable in system. Also double check that system has been sized correctly..

[ENERGY-MW]

During adjustement I connected energy meter (showing live power kW) and heat meter, comparing to Copeland characteristic the compressor power kW was too high for water temperature 35'C, and I thought the gas is overfilled. I did blow off in the same time following energy and heat metere readings - trying to find best COP. Result was not good, the compressor power was reduced a little, but heat production was reduced more - COP went down, as well condensing was not copleate anymore (sight glas bubles). Haw to calculate right amount of gas in system?

I have www in latvian but you can take a look on pictures www.draugiem.lv/siltumsuknis

[AlexG]

How did you calculate your condensor? Did you add compressor power to cooling capacity?
If you blow off gass, remained refrigerant is R134a. Pressure must go down.