Heat Recovery System

skittles11

I'm looking around at heat recovery systems and have come across what seems to be a relatively new system. It works in conjunction with an air to water heat pump a d works out a good bit cheaper. Below is extracted from the email the supplier sent me (very reputable supplier btw)

*This system extracts from the wet rooms, utility and centrally in the kitchen to bring the warm waste air back to the heat pump system. If there is enough energy from these areas this heat is used and the compressor outside won’t turn on.


With this however we are not supplying warm air back into the house, instead we are slowly drawing in air for outside through wall vents


The end result is a nicely ventilated but warm house and the costs reduce as you don’t need to buy the huge amount of ducting like you would with a standard HRV system.*

Does anyone have any experience or opinions with this type of system?

Thanks in advance.

Calahonda52

Am a bit dubious about the efficiency issues here: if you want PM me a link for a look see.

The cost argument is a fallacy because it looks only at capital cost and ignores running cost.
Conceptually the idea of cold damp air being mechanically drawn into my house is anathema to the science

Water John

Like Caladona, would be always interested in new options but I would be sceptical of what is described.

YoungAndBroke

Hi, I am doing a new build too and am looking at a number of similar options whether as an addon to an A2W HP or there are a few separate standalone hot water heat pump driven off air extracted from the house. It's hard to get exact figures from suppliers as to what combining them gives you. Which systems were you looking at? Do you mind if I pm you to discuss?

Water John

I see no harm in ye putting up links to the info on these. You are not selling/promoting them, just adding to the knowledge pool for discussion.

Every one going PM defeats the purpose. I and others want to benefit too from Honda'a opinion.
As I say,a bit dubious. Are they looking to get a slice of the €5K a heat recovery system would cost?

YoungAndBroke

Cheers Water John, I agree. If I have overstepped the mark with anything below, let me know

I have split these into 4 system types

Systems 1 and 2 below are transferring heat from the air drawn out of the house into your dhw and/or heating system but has no air to air transfer. With this in mind, you would need to be installing a demand control type ventilation system as opposed to MHRV. Options 1 and 2 seem to match in price to the extract fan needed for a DCV setup so if you're happy with DCV, the ROI is probably there

1) Combine Ventilation unit with heat pump to provide both heating and dhw

Nibe F135 module for use with their A2W heat pumps. I not allowed post a link here but do a search to find out about any of these

I can't find any other suppliers with this setup for A2W. There is a similar setup with a Nibe ground source that is transferring the heat from air to the ground called the FLM. Danfoss have the Danfoss Vent for ground source heat pump but the Irish suppliers called this fiddly and don't want to install it.

2) A heat pump that works off internal exhaust air and can be used to heat hot water only

Oschner europa mini iwp solar boiler

The Oschner supplier said to revent the cooled air back into a house for a larder or other room you might need to cool but not sure how this would work with DCV as you wouldn't be creating any negative pressure to draw air in. In fairness, they are heating suppliers, not ventilation experts.

This seems to be a common enough setup warranting its only set of tests from WPZ

There are a couple of these water heaters out there but the oschner suppliers were the only ones I could find who knew anything about them.

3) A ventilation system with a heat pump backup. Nilan Compact P Geo or Air seems to be most popular choice here in Ireland. I am trying to find someone to talk about the Genvex but no luck. This option may be more expensive to install and run than going with a separate HP and a separate MHRV so what is the advantage?

4) There are a number of exhaust air systems that seem to rely totally on the air coming from your house for both DHW and heating. I haven't really looked into these as I can't see how it would work. "Lisa, in this house, we obey the laws of thermodynamics"

My reasoning for looking into these is that our house is effectively in two parts with the south and west getting a lot more heat through solar gain and will be where we will be living for the most part and then the north and east part of the house contains the bedrooms, a couple of bathrooms and a study. I don't particularly want to be pumping warm air into these north and east rooms throughout the day when no one will be there. I would prefer to use the thermostats in the rooms to divert the heat where is needed through my heating and ufh system. I also think that such a setup might help with cooling in the summer months also. I might be over-thinking this

hochnie

Just to resurrect this thread for a bit.

I am looking at different options for refurb/selfbuild for ventilation. I have looked in to the MVHR systems and I am close to pulling the trigger on a system but have some reservations on efficiency and cost for our particular design.
It is complicated by half the building limiting the ability to run ducting due to the nature of the structure(600mm stone rubble walls,long and narrow)

I also like the idea of the NIBE F135 in combination with some smart DCV inlets as it reduces the ducting that I would need to run but the only information I can find online about how it could manage ventilation and energy recovery is that it is controlled by the NIBE indoor unit. Which is fine as long as the indoor unit can integrate with third party smart inlets as Nibe don't produce these as far as I can see.
Has anyone any experience of this F135 system? or an opinion on the other possibility of decentralised heat recovery systems such as
the NIBE DVC-10?

any thoughts are appreciated