Hello everyone,
I have the following description from the general contractor. I notice that the domestic hot water storage tank is much smaller than in other examples here in the forum. Does this make sense?
Are there any experiences with this type of unit(s)?
Is a circulation system necessary?
Which screed is recommended for underfloor heating?
(About the house: 166 m² (1786 sq ft), approx. 9 x 11 m (30 x 36 ft), KFW 55)
Heating system
Vaillant system:
Gas condensing boiler with integrated solar system according to DIN/EN 677, auroCOMPACT series in compliance with the energy saving regulation, featuring a stainless steel heat exchanger. Rated heating output is approximately 3.3 to 14.7 kW. Depending on the outdoor temperature, a weather-compensated solar system controller type multiMATIC regulates the temperature level. Heating cycles and domestic hot water production can be programmed individually via a timer.
Air/exhaust system:
The air/exhaust system for the sealed combustion condensing units is a concentric air/flue pipe system routed through the roof.
Domestic hot water
Vaillant system:
The house’s domestic hot water supply is central without circulation pipes. For supplying the bathroom, guest toilet, and kitchen, the described gas condensing boiler with integrated 190 L (50 US gallons) stratified hot water storage tank is combined with three system-matched flat-plate solar collectors of type auroTHERM VFK 145 V/H, mounted on the roof with a total collector area of about 7.5 m² (81 sq ft). A thermostatic mixing valve is provisioned to prevent scalding.
Underfloor heating:
Warm water underfloor heating designed based on heating demand calculation, using plastic piping on insulation boards with room temperature control (surface-mounted thermostat).
Depending on the contractor’s choice, either a cement or anhydrite screed will be installed.
One heating circuit manifold per floor is planned, which will be installed flush with the wall.
Thank you,
h4nnes
I have the following description from the general contractor. I notice that the domestic hot water storage tank is much smaller than in other examples here in the forum. Does this make sense?
Are there any experiences with this type of unit(s)?
Is a circulation system necessary?
Which screed is recommended for underfloor heating?
(About the house: 166 m² (1786 sq ft), approx. 9 x 11 m (30 x 36 ft), KFW 55)
Heating system
Vaillant system:
Gas condensing boiler with integrated solar system according to DIN/EN 677, auroCOMPACT series in compliance with the energy saving regulation, featuring a stainless steel heat exchanger. Rated heating output is approximately 3.3 to 14.7 kW. Depending on the outdoor temperature, a weather-compensated solar system controller type multiMATIC regulates the temperature level. Heating cycles and domestic hot water production can be programmed individually via a timer.
Air/exhaust system:
The air/exhaust system for the sealed combustion condensing units is a concentric air/flue pipe system routed through the roof.
Domestic hot water
Vaillant system:
The house’s domestic hot water supply is central without circulation pipes. For supplying the bathroom, guest toilet, and kitchen, the described gas condensing boiler with integrated 190 L (50 US gallons) stratified hot water storage tank is combined with three system-matched flat-plate solar collectors of type auroTHERM VFK 145 V/H, mounted on the roof with a total collector area of about 7.5 m² (81 sq ft). A thermostatic mixing valve is provisioned to prevent scalding.
Underfloor heating:
Warm water underfloor heating designed based on heating demand calculation, using plastic piping on insulation boards with room temperature control (surface-mounted thermostat).
Depending on the contractor’s choice, either a cement or anhydrite screed will be installed.
One heating circuit manifold per floor is planned, which will be installed flush with the wall.
Thank you,
h4nnes
With 3 collectors, I would recommend at least a 300-liter (79 gallons) tank for a south-facing roof with an inclination between 25° and 45°. Alternatively, it might be better to use one less collector with a 190-liter (50 gallons) tank. Otherwise, there could be a risk of overheating in summer if it is not a drain-back system.
From a hygiene perspective: 30-50 liters per person per day. Ideally, a complete exchange of water daily should be aimed for.
4 people, high demand = 200 liters
3 people, medium demand or 4 people, low demand = 120 liters
There are also collectors that can be turned off. Alternatively, you can omit the collectors and meet legal requirements through other means. With controlled residential ventilation, this is definitely not a problem.
4 people, high demand = 200 liters
3 people, medium demand or 4 people, low demand = 120 liters
There are also collectors that can be turned off. Alternatively, you can omit the collectors and meet legal requirements through other means. With controlled residential ventilation, this is definitely not a problem.
Is it generally possible to choose a different gas heating system? For just under 170sqm (1,830 sq ft) and KFW55 standard, you have an estimated heating load of 5-6kW at a design temperature of -12°C (10°F).
Most of the time, the minimum output (3.3kW) will still be too high, which will cause short cycling. This affects the lifespan.
Most of the time, the minimum output (3.3kW) will still be too high, which will cause short cycling. This affects the lifespan.
If four people shower one after another, we need 190 liters (50 gallons), but that amount is sufficient. So, the storage tank doesn’t need to be larger. I would ask why there are three collectors with such a small storage tank. Also, isn’t the heating system too powerful? That’s another question I would raise. Karsten
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