Hello everyone,
I have been following this forum for a while and would now like to ask for your advice or help.
We are planning to build a house this fall. Currently, we are in the preliminary decision stage regarding which heating system to use. Our shortlist includes:
1. Heat pump with ground collectors + solar thermal system + water-based fireplace + ventilation system with heat recovery
2. Gas condensing boiler + solar thermal system + water-based fireplace + ventilation system with heat recovery
We aim to achieve KFW 55 standard.
Here are some details about the house:
Heated living area: 250m² (2690 sq ft)
3 full floors (including 1 basement)
U-value ceiling: 0.13 W/m²K (0.023 Btu/h·ft²·°F)
U-value exterior walls: 0.19 W/m²K (0.034 Btu/h·ft²·°F)
U-value ground slab: 0.16 W/m²K (0.028 Btu/h·ft²·°F)
U-value windows: 0.9 W/m²K (0.16 Btu/h·ft²·°F)
Is there anything missing?
What do you think of the plan, and which of the two options would you recommend and why?
In the case of the heat pump, would it be more sensible to use photovoltaics instead of solar thermal to power the pump?
It would be great if some of you could comment on the project.
Thanks in advance for your efforts and have a nice evening.
Best regards
ha_celine
I have been following this forum for a while and would now like to ask for your advice or help.
We are planning to build a house this fall. Currently, we are in the preliminary decision stage regarding which heating system to use. Our shortlist includes:
1. Heat pump with ground collectors + solar thermal system + water-based fireplace + ventilation system with heat recovery
2. Gas condensing boiler + solar thermal system + water-based fireplace + ventilation system with heat recovery
We aim to achieve KFW 55 standard.
Here are some details about the house:
Heated living area: 250m² (2690 sq ft)
3 full floors (including 1 basement)
U-value ceiling: 0.13 W/m²K (0.023 Btu/h·ft²·°F)
U-value exterior walls: 0.19 W/m²K (0.034 Btu/h·ft²·°F)
U-value ground slab: 0.16 W/m²K (0.028 Btu/h·ft²·°F)
U-value windows: 0.9 W/m²K (0.16 Btu/h·ft²·°F)
Is there anything missing?
What do you think of the plan, and which of the two options would you recommend and why?
In the case of the heat pump, would it be more sensible to use photovoltaics instead of solar thermal to power the pump?
It would be great if some of you could comment on the project.
Thanks in advance for your efforts and have a nice evening.
Best regards
ha_celine
fragri schrieb:
without a large panoramic glass because only in this way can enough power be transferred into the water (around 30 kW per burn in our case).... What exactly is being supplied here, a commercial operation? 30 kW is the theoretical output at a single operating point; how much energy is actually usable during the burn can be measured with a heat meter.
I wouldn’t want to know the specific fuel consumption (SFC) of this setup.
Best regards
Hello Euro,
if I burn 10kg (22lbs) of hardwood, I get a calorific value of about 40kWh (4kWh/kg).
With a water content in the tiled stove of 70%, around 28kWh is transferred to the water.
Okay, ideally without losses!
To heat the storage tank (900L (238 gallons)) by, for example, 40K (40°C (72°F)), I need roughly 43kWh (m * Cp * deltaT).
Heat quantity meters will be installed for monitoring... I can report back later.
The boiler of the tiled stove is suitable as the sole heating system for buildings with a heat demand of up to 9kW.
I know people who don’t use an additional gas condensing boiler and manage with this system without feeling cold in winter... however, they do burn 30 to 40kg (66 to 88lbs) of wood per day.
Regards, fragri
if I burn 10kg (22lbs) of hardwood, I get a calorific value of about 40kWh (4kWh/kg).
With a water content in the tiled stove of 70%, around 28kWh is transferred to the water.
Okay, ideally without losses!
To heat the storage tank (900L (238 gallons)) by, for example, 40K (40°C (72°F)), I need roughly 43kWh (m * Cp * deltaT).
Heat quantity meters will be installed for monitoring... I can report back later.
The boiler of the tiled stove is suitable as the sole heating system for buildings with a heat demand of up to 9kW.
I know people who don’t use an additional gas condensing boiler and manage with this system without feeling cold in winter... however, they do burn 30 to 40kg (66 to 88lbs) of wood per day.
Regards, fragri
fragri schrieb:
...if I burn 10kg of hardwood, I get an energy content of about 40 kWh (4 kWh/kg)... Correct, but this amount must also be accepted/usable. ;-)fragri schrieb:
...With a water content in the masonry heater of 70%, 28 kWh go into the water... Actual energy or just theoretical power output? Pure theory, practically completely irrelevant.fragri schrieb:
...Ok, ideally considered without losses!.. Then just wait for the heat meter, the reality check will definitely come! ;-)fragri schrieb:
..To heat the storage tank (900 liters) by, for example, 40 K, I roughly need 43 kWh (m*CP*deltaT)... Sure, and not just pure theory? Could volume flow rates, the size of the heat exchanger surface area, and its position within the storage tank also play a role? ;-)fragri schrieb:
....Heat meters for monitoring will be installed... I can report back then.... I’m looking forward to it!fragri schrieb:
....The boiler of the masonry heater is suitable as the sole heat source for buildings with a heating demand up to 9 kW..... 30 kW water-side? How is the heat distribution from the masonry heater implemented on the heating side?Best regards.
Hello Euro,
no no… I made a typo… not 30 kW… I meant 30 kWh per firing.
The tiled stove has about 10 kW on the water side. The nominal heating capacity is 15 kW. We can adjust the volume flow (flow measurement) and there is an adjustable pump.
Of course, the correct design of such a system is crucial… just like with other heating systems.
no no… I made a typo… not 30 kW… I meant 30 kWh per firing.
The tiled stove has about 10 kW on the water side. The nominal heating capacity is 15 kW. We can adjust the volume flow (flow measurement) and there is an adjustable pump.
Of course, the correct design of such a system is crucial… just like with other heating systems.
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