MULTI-FUNCTION HEAT PUMP,MFHP 1

[Welchita]

A very classic question: I would like to know what the Forum has to say about the MFHP, (air cooling/heating + hot water production from the same unit/equipment) in special, those with the cooling effect power between 5 and 15 kW (or between 17,000 ~ 50,000 BTU/h). Any related comments, data, references, sites, hints, whatsoever, will be very appreciated. Thank You!

Happy New Year to ALL!
Welch

 

[Welchita]

Hello There!!

No one to comment this thread ?
Please, may we read your your expertise, experience.
Thank you,
Welch

 

[stanlsimon]

One advantage is that the summertime domestic hot water production is using "waste" heat. On the other hand wintertime hot water comes at a loss to the buildings heating requirements. You might want to go to the next larger sized heat pump. However hot water demand is generally sporadic, (A peak demand can be handled by putting in a bigger tank).

The heat pump would be roughly 3 times more efficient than electric resistant heating. I'm not sure of what you are comparing it to.

One disadvantage is the idea of putting all your eggs in one basket. If the heat pump goes down, you also loose your hot water.

I hope that I understood your question.

Sincerely,
Stan Simon

 

[Welchita]

Hi Stan Simon!

Thank you for replying. You got clearly my question!

As you said, in wintertime, when consumption/ sanitary hot water, CHW, compites with heating function so we usually introduce control routines to give priority to CHW.
As soon as the temperature gets to the set-point in tank, then it turns to the heating mode.

About the eggs..., I agree, but i think you have the same issue with your boiler at home. However, since wall gas-boiler are very competitive in price now-a-days, we can have one as a backup system for those situations, while we are waiting for the technician, I mean if are not the tech himself...

My second aspect is to get some feedback from your experience/knowledge about the whole real efficiency from the point of view of the installer engineer or/and from design engineer, if that's possible.

A third aspect: If at a first sight, such kinf of equipment, it seems such a good solution, mean COP/EER around 3 to 4 comparing with electric/gas boiler, why are not those equipments applied more often, I mean in US or Europe ??
Thank You. Kind Regards.
Welch

 

[stanlsimon]

Welchita,

You raise some good questions.

Redundancy is a way to improve reliability. The Econar heatpumps maunufactured here in Minnesota are available with dual compressors for that reason.

There are a lot of variables that need to be fixed in order to evaluate the performance of these multifunction units. I'm not sure if the industry has a standardized set of conditions for ratings. Generally if the unit uses dual compressors you are going to be well off, because the unit will be more able to match the typical load profile. Also a variable speed fan increases efficiency. Econar or Climatemaster may have some canned calculations to give you an idea of how many btu's or joules you might save.

One disadvantage of a desuperheater water heater is that you have an additional pump to buy and fiddle with.

As to why these units are not used as much as gas burning or electric resistance heating, the answer is the initial cost of a geothermal heat pump system is much higher.

Are you thinking about geothermal or air to air heat pumps?
Also what type of climate are you in?

Sincerely,
Stan Simon