ᐅ Mechanical ventilation with heat recovery as a heating system?

Created on: 16 Dec 2010 19:50
F
feud
Hello everyone,

We are currently planning a detached house of about 130m² (1,400 sq ft), with a basement, built with calcium silicate bricks and external thermal insulation composite system (ETICS) to KfW 70 standard, using a gas condensing boiler and solar collectors for domestic hot water.

According to our energy consultant, achieving this without a mechanical ventilation system with heat recovery is not feasible, and due to our construction method, controlled ventilation is advisable anyway.

My question is:
Would it make sense in this case to install a mechanical ventilation system with heat recovery and then use an additional electric heating element within the heat exchanger to provide heating through the ventilation system, thereby completely eliminating the conventional heating with the gas condensing boiler?

Thank you for your feedback.
F
feud
21 Dec 2010 08:58
Thank you, gentlemen, for your explanations. Since I fortunately meet the necessary requirements, I am also not at risk of misinterpreting the statement about the efficiency of heat recovery.
E
Erik_I
11 Jan 2011 15:48
Basically, a mechanical ventilation system with heat recovery has several advantages and, of course, a few disadvantages. The benefits include, besides energy savings:
- automatic fresh air supply
- no drafts
- prevention of mold growth
- noise protection, and
- pollen-free indoor air for allergy sufferers

Disadvantages can be:

- additional costs for the system technology
- not suitable for those who prefer lots of fresh air
- no special subsidies

The greatest energy savings come from the mechanical ventilation system itself. If you want to implement a passive heat recovery system with a heat exchanger, as in your case, more than 90% of the heat from the exhaust air can be recovered. Heat recovery systems are also approved as alternative measures under the Renewable Energies Heat Act and must achieve a heat recovery rate of at least 70% and a performance factor of 10. Since you already use solar collectors for domestic hot water preparation, this requirement does not apply to you but provides guidance on the necessary system quality. In addition to your architect and energy consultant, the heating and air conditioning specialist is an important contact.

In principle, I would recommend considering including heating support via the solar collectors in your planning, at least from a technical system perspective. Besides adjusting the heating system, a different type of hot water storage tank will be required during installation, and a larger collector area will be necessary.
B
Bauexperte
11 Jan 2011 16:00
Erik_IEU schrieb:
...Basically, I would suggest considering the integration of solar collectors for heating support at least from a technical system perspective in your planning...

I would like to understand a logical and thus comprehensible reason for using such a system....

Looking forward to your insights
€uro
11 Jan 2011 16:47
Erik_IEU schrieb:
....The greatest energy-saving effect comes from the controlled ventilation system itself.
Well, I would reconsider that.
Erik_IEU schrieb:
....If you want to implement, as in your case, passive heat recovery with a heat exchanger, up to 90% or more of the heat from the exhaust air can be recovered.
What would an active one be?
Erik_IEU schrieb:
....Basically, I would still consider including, at least technically, heating support via solar thermal collectors in your planning.

Well, Erik_IEU is clearly not a building services engineering specialist.

Regards.

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