Heat pump water heater

[minguinhirigue]

Last sensitive point, the temperature of the domestic hot water.

Everyone knows that the COP of PACs collapses with the temperature difference ...

Already for low temperature heating (underfloor heating or air heater), the winter temperature delta is limited (20 to 30 ° C), but then for domestic hot water at 60 ° C?

The only solution high tech which seems interesting implies a 'significant' investment and a technicality which not everyone knows how to deal with: It is the VMC and heat pump coupling on stale air.

For a house with 5 rooms and 3 people
- DHW requirement: approx. 4000 kWh / year
- Air flow: 105 m3 / h for a 5-room house, 919800 m3 / year
On the basis of a global energy calculation, we need to "take" about 18 ° C of the stale air (0,24 Wh / K.m3) from the house to cover the DHW needs.

The problem is less clear when we take into account the actual temperatures:
- T. stale air in summer: 24 to 30 ° C.
- T. stale air in winter: 19 to 26 ° C.
- Medium water T.: 14 ° C.
- DHW temperature: 60 ° C ...

But the system remains interesting because it recovers energy lost in winter, and the COP operates on a source at constant temperature and "high" compared to the outside air in winter.

It is operated by manufacturers such as OSCHNER with all in one systems (VMC + DHW Heat Pump).

However, hello for repairs!

[bernardd]

It would be even more interesting and efficient to recover the heat from the hot water before going back to the sewers.

And also smoke from a pellet stove, but we talk about it on another thread :-)

And considering the diagram of Oschner presented before, to use the air leaving the house for the combustion of the wood heating: air already hot, and I think that the water vapor could well improve the combustion, which I would like to check ....

[Forhorse]

Already for low temperature heating (underfloor heating or air heater), the winter temperature delta is limited (20 to 30 ° C), but then for domestic hot water at 60 ° C?

On the one I saw there is an extra electrical resistance.
So as much to say that the interest is limited and that the thing will never be amortized

[bobono]

For a year I have installed a second-hand thermodynamic water heater 800 € for 300 liters

(A lot of installation done by non-specialist, moreover not passionate about RE does not work or is not satisfactory.)

The price is justified there knowing that the new cost much more 2000 € to 3000 €. But the prices fall.

The tank is of quality e vitrify (and not simple enamelling) two coils in the tank for different use, water heater is equipped with a coil with fin for the transmission of heat from the gas fridge to the water.

Compared to a conventional water heater, the insulation is reinforced.

A meter allows me to track consumption 100 kw for a month 3 people. 3 kw day I recall a classic resistance water heater just to maintain.
A little reminder of hot water for a family is 1/3 of the electric consumption
for those who are electrically equipped of course.

[dedeleco]

Interesting information, profitable for a second-hand purchase, much more quickly amortized than if new, which is amortized in 10 to 15 years of consumption (unless the electricity increases) and if the heat pump unit does not fail before , and if the maintenance costs are not high ??????

My experience heat pump for house heating in department 83, has the unfortunate experience of heat pump quickly broken down and not very repairable, without buying everything, by scam on the fluid almost obsolete with the purchase.

Reliability is very important for calculating depreciation.

[Other]

Hello

I heat and air condition my house fully with a heat pump, the system provided even when the outside temperature drops to -25C
where it becomes profitable it is summer when I air condition I make hot water or two 60 gallon tanks (200litres each)
the system has been operational since the early 90s
at the beginning I made hot water in winter ie the water from the aqueduct made around 4C to 6C in winter with the heat pump I raise it to more than 40c (I can raise it to 50c see 55C but the efficiency and so insignificant that it is better to finish rising to its temperature by the electric elements of the tank

The compressor draws 2 5 amperes at 230 volts


Andre