ᐅ Heat Pump with Photovoltaic System vs. Gas Heating and Solar Thermal Energy

Created on: 7 Jun 2016 21:53
I
inconel
Hello everyone,

for my house construction, which will start next year, I would like to gather information about the heating system, specifically regarding the two options:
+ Gas condensing boiler, supported by approximately 12m² (130 sq ft) of solar thermal panels and a wood stove
+ Groundwater heat pump powered by a photovoltaic system

About the property:
+ Planned is a 10x11m (33x36 ft) house with two full floors, a basement, a hip roof with about 35m² (375 sq ft) of south-facing roof area, and approximately 200m² (2,150 sq ft) of living space.
+ Exterior walls made of 36.5cm (14 inches) perlite-filled bricks “Poroton T7”
+ Location: Bavaria, with an average annual solar radiation of about 1000 kWh/m²

Option 1: Gas condensing boiler
Advantages:
- Proven, durable gas condensing technology (efficient)
- Fast response time of the gas heating system, requires no long preheating
- From around April to October, the thermal energy from the solar panels is sufficient (no gas needed); in winter, supported by the wood stove for both hot water and heating

Disadvantages:
- Solar panels need to be cooled relatively early in summer, meaning little hot water is required but excess heat must be dissipated from the panels → increased electricity and water costs without added benefit
- Large domestic hot water storage tank needed to utilize countercyclical heating periods

Option 2: Photovoltaics with heat pump
Advantages:
-
Autonomous heat and electricity production
- “Green energy”
- Additional support for other continuous electricity consumers (refrigerator, freezer, washing machine, dryer)
- Relatively low effort to install suction and discharge wells, as groundwater is already available at about 2.5m (8 ft) depth

Disadvantages:
- High investment costs for both photovoltaic system and heat pump (long payback period)
- Limited sunshine during months with high energy demand
- Complex and expensive, but still necessary, storage solutions for photovoltaic electricity

I hope you can understand my concerns and ideas, and I would really appreciate your feedback. How do you see the situation? What do you think is truly practical?

Thank you very much

Best regards
G
Goldi09111
18 Jun 2016 14:27
I agree here.

Our architect (who will probably handle the planning) also prefers to install brine heat pumps but without controlled mechanical ventilation, which concerns me a bit given today’s insulation standards. I find the option of installing photovoltaic systems later quite interesting since I believe energy storage will play a crucial role in the future.

But the fact is that, from an economic point of view, as things stand today, a condensing gas boiler is the best solution.
MarcWen18 Jun 2016 17:30
Goldi09111 schrieb:

But the fact is, from an economic standpoint as of today, a gas condensing boiler is the best solution.

That may be true, but in many cases, their installation is not allowed, or they cannot be combined with solar thermal systems.
B
Bauexperte
18 Jun 2016 19:08
Goldi09111 schrieb:

But the fact is that, from an economic perspective as of today, a gas condensing boiler is the best solution.
I am looking forward to the reasoning behind this statement


Bauexperte
G
Goldi09111
18 Jun 2016 22:49
What does statement mean?!

Simply take the investment costs and the current operating costs and compare them. Of course, nobody knows these unknowns (electricity and gas costs) in the future.
B
Bauexperte
18 Jun 2016 23:18
Sorry – but then you have no idea what kind of investment you need to make to build a single-family house according to current energy saving regulations using gas.

Bauexperte
G
Goldi09111
19 Jun 2016 09:29
Is it really that much more difficult according to the current energy-saving regulations?

I am not that knowledgeable in this field, which is why experts like you exist and are paid to always stay up to date.

I was under the impression that it is still allowed to build with gas, controlled ventilation, a certain level of insulation, and without solar thermal systems even under the new energy-saving regulations.

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