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Combined Hot water tank and ASHP - any advice welcome.


cbk

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Has anybody fitted one of the combined DHW and ASHP units?  Was at NEC show last week and saw a unit made by Haier - CURV - HP200M3 that seems a neat solution  optimised for DHW use.   For my set-up the air inlet could be linked to a bathroom and would replace a wall mount extractor fan and allow the unit to recover heat  from extracted air as input to DHW as well.   It would also allow main ASHP to be smaller and used only for UFH.

Any experience good or bad welcome.

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Brochure says ' Corrosion protection - Magnesium rod'.  I guess this means it is not a stainless tank and rod acts as an anode?  Routine replacement would most likely get overlooked so not such a good idea.  But maybe there are other types with a stainless tank.

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I have a similar set-up.

 

A few comments:

 

We completed our self build in 2020 and have a home with a good level of insulation. I did'nt need the cylinder to do space heating for us.

We have three extract points, en-suite, bathroom and utility room.

As a way to provide domestic hot water heating for a family of four, the capital cost is cheap compared to getting an external heat pump fitted. 

Our tank and system is a Joule Aero, with stainless steel cylinder, no need for anode changes. I believe they have now released a new model. I live in soft water area.

The system also has a dual immersion electric heating, but never used it and rely entirely on the mini heat pump. 

All in we are about 10-12kWh of electricity each day, but not sure how much of that relates to the heat pump.

I'm not sure why the system is not popular here, when I posted a few years back, one member suggested that I would hear whistling through our trickle vents when the system was running which was nonsense.

 

After living with the system for coming up to two years, I'm so glad we fitted this system rather than external air source heat pump, as it fits our circumstances well.

 

 

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14 hours ago, SteamyTea said:

Was it @Gone West who fitted an exhaust air one at his old place.

 

I think the OP is talking about the Ecocent type device which is a DHW tank with a small ASHP on the top although not heard od Haier. I had a Genvex Combi 185LS which was a combined MVHR, DHW tank and EASHP where the EASHP heated the water tank and the output from the MVHR.

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5 minutes ago, Gone West said:

I think the OP is talking about the Ecocent type device which is a DHW tank with a small ASHP on the top although not heard od Haier. I had a Genvex Combi 185LS which was a combined MVHR, DHW tank and EASHP where the EASHP heated the water tank and the output from the MVHR.

Yours was a good unit though and it did the job.  I have wondered if it would work in my small place.

 

HEAT RECOVERY VENTILATION APPLIANCES WITH AIR TO WATER HEAT PUMP
 
The award winning Pichler PKOM 4 (2018) and Genvex Combi 185 (2013) systems provide balanced whole house ventilation, incorporating a high performance counter-flow heat exchanger to recover the heat otherwise lost via the exhaust air. This negates the use of trickle vents, preventing cold draughts from being drawn into habitable rooms. In addition to this heat recovery ventilation they can also provide space heating to the supply rooms and heat up a tank of domestic hot water.
 
They are particularly well suited to highly insulated homes with a small heating and domestic hot water demand.
 
The PKOM 4 which won a Build It 'Best Sustainable Heating Solution' award in 2018, has TWO heat pumps, one 1.3kw heat pump to provide space heating and COOLING and one dedicated to heating 212 litre of water in it's integral water cylinder.

The Combi 185's integrated air source heat pump prioritises the production of domestic hot water and will provide space heating when the 185 litre cylinder has been fully charged. The heat pump is able to produce about 380 litres of hot water every day.

In well insulated homes, some of our clients have found that there is no need for additional heating except a heated towel rail in the bathrooms and in the winter months, a wood-burning stove.

Both units have very compact footprints with the PKOM 4 measuring 741 mm x 734 mm and the Combi 185 at 600 mm x 700 mm (the space previously occupied by a hot water cylinder) and has a low servicing requirement.
 
The heat recovery matrix is 95% efficient and the hot water cylinder can be connected to a second heat source such as solar panels. A pollen filter is fitted as standard on the supply air to the house.          
 
Both units are suitable for smaller apartments/townhouses where lower ventilation rates are required.
 
Typically these systems are suitable for up to four-person occupancy.
 
 
 APPLIANCE
LIVING AREA (M2/SQFT)
AIRFLOW (M3/H)
Min   /   Max
PRESSURE (PA)
 Combi 185 S (spec sheet)

292   /   3,143

100    /   350

125

 Combi 185 LS (spec sheet)

292   /   3,143

150    /   350

125

CombiWithArrowsWeb.jpg

Edited by SteamyTea
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4 minutes ago, SteamyTea said:

Yours was a good unit though and it did the job.  I have wondered if it would work in my small place.

I think the key sentence from that report was: "They are particularly well suited to highly insulated homes with a small heating and domestic hot water demand." I think mine was working at the limit of what it able to.

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1 minute ago, Gone West said:

I think the key sentence from that report was: "They are particularly well suited to highly insulated homes with a small heating and domestic hot water demand."

That is me then.  Yesterday I used 7 kWh.  That included a bath.

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2 minutes ago, Gone West said:

With that usage you could buy a lot of electricity for the cost of the Genvex.

This is constantly the problem.

Even on the coldest of days, I use 30 kWh/day, and then only for a few days.

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