ᐅ Diagram of an air-to-water heat pump system with two storage tanks
Created on: 22 May 2018 00:41
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bauibauiHello,
after deciding to go with an air-to-water heat pump (for now), I’m currently thinking about the (ideal) system layout. There’s a lot of discussion about incorrect temperatures in stratified tanks, using two separate heat pumps for domestic hot water and heating, excessively high flow temperatures, and so on. Conditions: 150 sqm (1600 sq ft) living area, 4 people, underfloor heating, renovated older building from 1965. My idea is as follows:
One heat pump and two storage tanks, one for domestic hot water (200 L (53 gallons)) and one for heating water (300-500 L (79-132 gallons)).
One heat pump that alternately fills the tanks as needed. When heating the storage for the heating system, it runs in an efficient range (flow temperature around 40°C (104°F)), but it is less efficient when heating the domestic hot water tank, since the flow temperature is higher at around 55°C (131°F).
If a photovoltaic system is added, surplus electricity would first be used for heating. If it’s not needed there, the domestic hot water tank could be heated fully—even inefficiently—up to 90°C (194°F). In that case, a mixing valve should be installed at the outlet to reduce the temperature to 50-55°C (122-131°F).
Does anyone already have a system like this in operation? What have your experiences been? Can a heat pump handle this kind of control, or as an electronics engineer do I need to design something myself?
I have space for two tanks, and I think combined stratified tanks and similar setups are neither fish nor fowl.
Regards
bauibaui
after deciding to go with an air-to-water heat pump (for now), I’m currently thinking about the (ideal) system layout. There’s a lot of discussion about incorrect temperatures in stratified tanks, using two separate heat pumps for domestic hot water and heating, excessively high flow temperatures, and so on. Conditions: 150 sqm (1600 sq ft) living area, 4 people, underfloor heating, renovated older building from 1965. My idea is as follows:
One heat pump and two storage tanks, one for domestic hot water (200 L (53 gallons)) and one for heating water (300-500 L (79-132 gallons)).
One heat pump that alternately fills the tanks as needed. When heating the storage for the heating system, it runs in an efficient range (flow temperature around 40°C (104°F)), but it is less efficient when heating the domestic hot water tank, since the flow temperature is higher at around 55°C (131°F).
If a photovoltaic system is added, surplus electricity would first be used for heating. If it’s not needed there, the domestic hot water tank could be heated fully—even inefficiently—up to 90°C (194°F). In that case, a mixing valve should be installed at the outlet to reduce the temperature to 50-55°C (122-131°F).
Does anyone already have a system like this in operation? What have your experiences been? Can a heat pump handle this kind of control, or as an electronics engineer do I need to design something myself?
I have space for two tanks, and I think combined stratified tanks and similar setups are neither fish nor fowl.
Regards
bauibaui
We will have only one storage tank, but it will include a fresh water station, allowing us to keep the storage temperature at 45°C (113°F) without any issues with legionella or similar concerns. Any surplus from the photovoltaic system after the battery storage will be used to raise the boiler temperature; if necessary, the excess energy will be fed back into the grid.
We have an integrated hot water storage tank (230L) set to 45°C (113°F). Since last August, it hasn’t even consumed 350 kWh. It takes quite a while to cover the costs for the control system, tank, etc. Are you looking for a complicated solution to a simple problem? Do you really need to run the supply temperature at 40°C (104°F)?
Using photovoltaic electricity to heat water with an electric heating element is extremely inefficient; it’s better to feed this electricity into the grid. If you want to use it for heating, then do so via a heat pump.
For controlling systems with photovoltaic power, you naturally need the appropriate equipment. However, this is common on the market and nothing special.
Lower the temperature for domestic hot water to 45°C (113°F).
For controlling systems with photovoltaic power, you naturally need the appropriate equipment. However, this is common on the market and nothing special.
Lower the temperature for domestic hot water to 45°C (113°F).
ares83 schrieb:
We have an integrated 230L (61 gallons) hot water tank set to 45°C (113°F). Since last August, it hasn’t even used 350 kWh. ?Hard to believe it’s less than 350 kWh over the winter.
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toxicmolotof22 May 2018 19:01tomtom79 schrieb:
Not even 350 kWh over the winter, hard to believe.That would be a realistic value only for domestic hot water... over 90 to 120 days.Similar topics