ᐅ Residential ventilation and dehumidification using a domestic hot water heat pump

Created on: 16 Oct 2017 02:11
P
Pitti
P
Pitti
16 Oct 2017 02:11
Hello dear forum community,

We are planning to build a house soon, for which the builder is relying on a greywater heat pump for ventilation and dehumidification.
Primarily, air will be drawn from the guest toilet, bathroom, and utility room and used for hot water production. Air from other rooms flows in to replace it, allowing for some air exchange. Fresh air is also intended to be supplied to the living spaces. I assume this will require wall openings in the living areas to the outside, as otherwise, in my opinion, not much air will flow in.

What do you think? Is this a good operating principle and fairly common for a house of about 130m² (1400 sq ft), or is it nonsense? Is the ventilation achieved this way sufficient to effectively prevent mold growth?

Thank you very much for your answers.
M
meister keks
21 Oct 2017 22:24
Hello.
The system provides significantly drier air in the house than usual, so I believe mold has no chance.

The supply air then comes through small openings in the ceiling.
B
BigFlow
23 Oct 2017 10:11
Hello,
we use this system as well. Air is extracted from the bathrooms, kitchen, and storage room. Everywhere else, there are humidity-controlled wall vents that allow fresh air to enter. We heat the water to 51 degrees Celsius (124°F), and so far, it works quite well.

However, the air inside the house is only drier if there is no significant moisture outside. In summer, it wasn’t possible without an electric dehumidifier when it was especially humid. How it will behave in winter remains to be seen.

If the hot water tank is completely empty, it takes about 10 hours to reach the set temperature again (without using the electric heating element). This should be considered if you like to take a full bath in the morning.

Energy consumption from June until now is around 300 kWh.
M
meister keks
24 Oct 2017 22:03
Hello.
How large is your water storage tank?
Ours is only 180 liters (48 gallons) and easily enough for 5 showers when we have guests.
We have the water temperature set to 63 degrees Celsius (145 degrees Fahrenheit).
B
BigFlow
25 Oct 2017 08:00
Our storage tank has a capacity of 200 liters (53 gallons). However, we have a bathtub measuring 190 x 90 cm (75 x 35 inches) with a usable volume of 210 liters (55 gallons).
A
Alex85
25 Oct 2017 08:43
But it will not be filled to the brim with 45°C (113°F) hot water, and besides water, a person also has to fit inside.