ᐅ How much buffer storage is needed for around 300 m²? Is installing cooling worth it?
Created on: 2 Feb 2024 08:07
A
Andik81
A heat pump is planned for an energy-efficient house 70. The living area is approximately 300 m² (3,229 ft²) spread over 2 floors. It consists of one large apartment and four small apartments. Underfloor heating will be installed throughout.
1.) What size should the buffer tank be? Is 400 liters (106 gallons) sufficient?
2.) Is the extra cost for a cooling function worth it? How many degrees can this roughly lower the room temperature?
1.) What size should the buffer tank be? Is 400 liters (106 gallons) sufficient?
2.) Is the extra cost for a cooling function worth it? How many degrees can this roughly lower the room temperature?
W
WilderSueden2 Feb 2024 12:26What are you planning that requires 500 liters (130 gallons) of hot water? Multiple residential units?
The volume also needs to be maintained at temperature.
The volume also needs to be maintained at temperature.
WilderSueden schrieb:
What are you planning that requires 500 liters (132 gallons) of hot water? Multiple living units?
The water volume also needs to be maintained at temperature.Yes, it is one large apartment and four smaller apartments.
J
jens.knoedel2 Feb 2024 12:29WilderSueden schrieb:
What are you planning that requires 500 liters of hot water? Multiple residential units?Five apartments – in that case, 500 liters could be quite small (what temperature is the water heated to, and how is it heated...?).If it’s only heated to 55°C (131°F) and five bathtubs are filled from that, it will be a rather cool bath!
I am fairly certain that for more than 4 residential units, different regulations apply for domestic hot water preparation (legionella prevention / thermal disinfection, etc.).
This leads to high energy consumption with a large hot water storage tank for the reasons mentioned above. Therefore, it might be worth seriously considering decentralized energy heaters (DEH) or instantaneous water heaters (or having a qualified MEP engineer evaluate these options). For long pipe runs, no more than 2 liters (about 0.5 gallons) of water should remain in the pipes (I am not sure about this figure, so it’s best to ask an MEP engineer) — pipe diameters, circulation, and so on.
This leads to high energy consumption with a large hot water storage tank for the reasons mentioned above. Therefore, it might be worth seriously considering decentralized energy heaters (DEH) or instantaneous water heaters (or having a qualified MEP engineer evaluate these options). For long pipe runs, no more than 2 liters (about 0.5 gallons) of water should remain in the pipes (I am not sure about this figure, so it’s best to ask an MEP engineer) — pipe diameters, circulation, and so on.
Cooling is worthwhile in my opinion especially if the heat pump can do it “anyway,” for example a brine-to-water heat pump with integrated “passive cooling.” This can provide a 2–3°C (3.6–5.4°F) difference that helps reduce peak temperatures during heat waves. My heat pump has this feature, and I have had positive experiences with it. However, I live in a passive house where a lot of effort has been put into summer thermal protection.
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