ᐅ Controlled Residential Ventilation with Cooling: Ground Source Heat Pump Using Brine Loop Instead of Air-to-Water Heat Pump?
Created on: 3 Jan 2019 22:37
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Christian K.
Hello everyone,
So far, I assumed that cooling with a mechanical ventilation system with heat recovery is done using an additional device that can be retrofitted later. This seems to be only partially true, as it is indeed an additional device, but retrofitting it later is difficult. Or are there systems that operate purely electrically? In our case, a photovoltaic system would be available, so we could technically cool using electricity in the summer.
Cooling with a mechanical ventilation system with heat recovery is done either with an earth-to-air heat exchanger (EWT) or a ground heat exchanger (ground loop). Since we need to raise the ground level by about 1.5m (5 feet), we could save on excavation work. It would be interesting to know what a ground heat exchanger would cost. So far, I haven’t found any concrete information because frequently only ground-source heat pumps are mentioned and not ground heat exchangers for mechanical ventilation systems, or if so, usually together with excavation work.
In my research, I came up with the idea of replacing our planned air-to-water heat pump with a ground-source heat pump. After all, I would have to install a system for cooling the mechanical ventilation anyway, so I could just extend the installation somewhat and switch to a ground-source heat pump, right? Or is it not that simple, and what disadvantages would there be? The costs are, of course, also interesting here, especially considering that we wouldn’t have additional excavation work.
I wasn’t able to find clear answers to these three questions and hope someone here can provide some clarification.
Good luck, CK
So far, I assumed that cooling with a mechanical ventilation system with heat recovery is done using an additional device that can be retrofitted later. This seems to be only partially true, as it is indeed an additional device, but retrofitting it later is difficult. Or are there systems that operate purely electrically? In our case, a photovoltaic system would be available, so we could technically cool using electricity in the summer.
Cooling with a mechanical ventilation system with heat recovery is done either with an earth-to-air heat exchanger (EWT) or a ground heat exchanger (ground loop). Since we need to raise the ground level by about 1.5m (5 feet), we could save on excavation work. It would be interesting to know what a ground heat exchanger would cost. So far, I haven’t found any concrete information because frequently only ground-source heat pumps are mentioned and not ground heat exchangers for mechanical ventilation systems, or if so, usually together with excavation work.
In my research, I came up with the idea of replacing our planned air-to-water heat pump with a ground-source heat pump. After all, I would have to install a system for cooling the mechanical ventilation anyway, so I could just extend the installation somewhat and switch to a ground-source heat pump, right? Or is it not that simple, and what disadvantages would there be? The costs are, of course, also interesting here, especially considering that we wouldn’t have additional excavation work.
I wasn’t able to find clear answers to these three questions and hope someone here can provide some clarification.
Good luck, CK
B
boxandroof30 Jan 2019 14:37If your new home tends to overheat significantly and you need to keep it cool all the time, then seriously consider installing a proper air conditioning system combined with solar panels, or at least prepare for it.
The mechanical ventilation with heat recovery already reduces overheating to some extent, but you won’t get much more benefit from it. It’s better to invest in effective shading and its control system.
Our mechanical ventilation system had a summer bypass mode with turbo cooling by default, but we switched it off because it didn’t have any positive effect.
Cooling with an air-to-water heat pump is just a “nice to have” for us, and having cold feet for one or two days isn’t an issue. Especially after the recent heatwave during the peak of summer, it was convenient to get the indoor temperature (max. 25°C (77°F) in our case) down more quickly.
Air conditioning everywhere for cooling is certainly appealing, but it mainly makes sense if you can cool actively and passively using a geothermal source continuously. Otherwise, I would prefer a conventional air conditioning system.
The mechanical ventilation with heat recovery already reduces overheating to some extent, but you won’t get much more benefit from it. It’s better to invest in effective shading and its control system.
Our mechanical ventilation system had a summer bypass mode with turbo cooling by default, but we switched it off because it didn’t have any positive effect.
Cooling with an air-to-water heat pump is just a “nice to have” for us, and having cold feet for one or two days isn’t an issue. Especially after the recent heatwave during the peak of summer, it was convenient to get the indoor temperature (max. 25°C (77°F) in our case) down more quickly.
Air conditioning everywhere for cooling is certainly appealing, but it mainly makes sense if you can cool actively and passively using a geothermal source continuously. Otherwise, I would prefer a conventional air conditioning system.
C
Christian K.30 Jan 2019 14:52We also considered only preparing for an air conditioning system and then installing it later if needed. We were sometimes told that having both a controlled ventilation system and air conditioning doesn't make much sense, so we wanted to inform ourselves about what is possible and practical. The following options would need to be suitable:
- Preparing for air conditioning (costs?)
- Cooling via an air-to-water heat pump. Most air-to-water heat pumps can do this directly, and then you just need to ensure that no condensation forms on the floor. This should involve very little additional cost and still provide some cooling.
- Controlled ventilation system with a heat exchanger (costs?)
For shading, we will use external blinds with automatic control. This should keep the house relatively cool. Therefore, we don’t want to invest unnecessary money but rather have an affordable option just in case.
- Preparing for air conditioning (costs?)
- Cooling via an air-to-water heat pump. Most air-to-water heat pumps can do this directly, and then you just need to ensure that no condensation forms on the floor. This should involve very little additional cost and still provide some cooling.
- Controlled ventilation system with a heat exchanger (costs?)
For shading, we will use external blinds with automatic control. This should keep the house relatively cool. Therefore, we don’t want to invest unnecessary money but rather have an affordable option just in case.
C
Christian K.30 Jan 2019 16:43Sand-lime brick with ETICS (external thermal insulation composite system). The largest windows are on the west side. On the south side, the following windows are installed (clear dimensions!):
Ground floor: 2x 245 cm (96 inches) wide / 70 cm (28 inches) high
First floor: Bathroom: 155 cm (61 inches) wide / 133 cm (52 inches) high; Office: 190 cm (75 inches) wide / 133 cm (52 inches) high
Attic: Bathroom: 245 cm (96 inches) wide / 70 cm (28 inches) high; Bedroom: 75 cm (30 inches) wide / 70 cm (28 inches) high
Ground floor: 2x 245 cm (96 inches) wide / 70 cm (28 inches) high
First floor: Bathroom: 155 cm (61 inches) wide / 133 cm (52 inches) high; Office: 190 cm (75 inches) wide / 133 cm (52 inches) high
Attic: Bathroom: 245 cm (96 inches) wide / 70 cm (28 inches) high; Bedroom: 75 cm (30 inches) wide / 70 cm (28 inches) high
A ground source heat pump is definitely a great solution. I built the collector myself. The total cost was under 2,500 euros. This pays off by itself thanks to the higher government subsidy for ground source heat pumps with an innovation bonus. Nibe (that’s the manufacturer of my heat pump) also, as far as I know, offers integration with controlled residential ventilation systems that provide cooling in summer.
However, we don’t use that feature. For me, the goal was to save on heating costs, and I didn’t want to install a noisy unit near my neighbors.
However, we don’t use that feature. For me, the goal was to save on heating costs, and I didn’t want to install a noisy unit near my neighbors.
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