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
C
Christian K.28 Jan 2019 16:33A few degrees would be enough for us. Last summer, for example, the living room in our apartment reached 28°C (82°F), while on the other side, the children's room was only 26°C (79°F). The children’s room felt noticeably more comfortable. It’s similar to a car: try adjusting the air conditioning from 20°C (68°F) to 17°C (63°F).
We will also use plenty of external blinds for shading, and the mechanical ventilation system with heat recovery is intended to support this at a relatively low cost. Proper shading, a summer bypass, and a cooling coil should make the summer more comfortable.
But you are absolutely right, this does not replace air conditioning, where the temperature can be set more or less freely. That also costs a bit more ;-)
We will also use plenty of external blinds for shading, and the mechanical ventilation system with heat recovery is intended to support this at a relatively low cost. Proper shading, a summer bypass, and a cooling coil should make the summer more comfortable.
But you are absolutely right, this does not replace air conditioning, where the temperature can be set more or less freely. That also costs a bit more ;-)
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Steffen8028 Jan 2019 20:35Christian K. schrieb:
For us, a few degrees would be enough. Last summer, for example, the temperature in our living room was 28°C (82°F), while on the other side in the children’s room it was only 26°C (79°F). The children’s room felt noticeably more comfortable. It’s the same in a car—just lower the AC setting from 20°C (68°F) to 17°C (63°F).
We will also have good shading with external blinds, and the mechanical ventilation with heat recovery is just meant to support it affordably. Proper shading, a summer bypass, and a cooling coil should make summer more pleasant.
But you’re absolutely right—this doesn’t replace air conditioning, where you can set the temperature more or less as you like. That costs a bit more ;-)Nice… and yet… with mechanical ventilation with heat recovery, it would still have been 28°C (82°F) in the living room and 26°C (79°F) in the children’s room, I bet! The cooling coil might (maybe) manage to cool down the high outside temperature… to what? 28°C (82°F) 🙂 using electricity 🙂 It all sounds very clever. But maybe you’ll at least get a nice brochure with it…
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Christian K.28 Jan 2019 20:43Hmm, but then favoring an air conditioning system. How is that supposed to be powered? With love? As you nicely put it, I doubt it! Whether it’s an air-to-water heat pump, air conditioning, or a coil that cools the air with electricity, it’s almost the same. If I want more cooling, I need more electricity. Sure, efficiency also plays a role here, before you start trolling again. And what the coil requires, the photovoltaic system will easily be able to supply in the summer.
Well, Steffen is right about that. The whole "cooling" of the air with the mechanical ventilation with heat recovery actually takes place right around the vents during summer. Infiltration from the sun, people, and activities inside the house will quickly ruin the targeted balance for you.
Steffen is right. The mechanical ventilation system for residential spaces has a ventilation rate that is too low when designed according to standards and does not provide enough capacity for cooling. Either the system needs to be designed differently, or conventional air conditioning units should be used. Be sure to plan all the connections at the same time.
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Steffen8029 Jan 2019 10:09Christian K. schrieb:
Hmm, but then favoring an air conditioner. What will power it? Love? As you so nicely put it, I bet not! Whether it’s an air-to-water heat pump, air conditioning, or a coil cooling the air with electricity, it’s almost the same. If I want more cooling, I need more electricity. Yeah, efficiency also plays a role before you start trolling again. And whatever the coil needs, the photovoltaic system will easily supply in summer.What I meant by "electricity" -> The controlled ventilation system doesn’t actually help and uses even MORE electricity (because of the coil) than the usual ~60 watts. An air conditioner also doesn’t consume much... but compared to that, it delivers significantly more 😉
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