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Solar Thermal Hot Water

What is solar thermal hot water?

Solar thermal hot water uses the heat of the sun to warm a tank of domestic hot water. It is cheap and environmentally friendly.

Worcester solar thermal hot water panels

Why do I need solar thermal hot water?

Somewhere between 11% and 25% of your energy bill is used for heating water.

Solar thermal is a good choice if:

you would like to reduce your energy bills
reduce your carbon footprint
improve the EPC value of your property

What makes up a solar thermal system?

The components of a solar thermal system are:

Hot water storage tank (cylinder).
Control panel.
Solar collector panel (normally on the roof).
Solar fluid (glycol).
Pumping station.
Temperature sensor in collector panel
Temperature sensor in hot water tank (cylinder).
Expansion vessel
Container for any release of solar fluid
Pipework.
Overheat thermostat for unvented cylinders.

How does solar thermal hot water work?

The temperature sensor in the tank tells the control panel hot water is required.
The controller compares the temperature in the panel to the temperature in the hot water storage tank. If the panel is not hot enough they system goes into standby. If there is enough temperature difference the controller tells the pump to start. This circulates solar fluid around the pipework to the panel.
The solar fluid slowly circulates through the panel back to the hot water tank in a constant loop. The solar fluid heats up in the panel and transfers that heat to the hot water cylinder.
When the hot water cylinder reaches the set temperature the system switches off. The pumping station stops circulating the fluid and waits for a new demand.

What are the benefits of solar thermal hot water?

Reduced energy bills. The energy saving trust estimate that a saving of £110 to £210 can be made from installing solar thermal hot water.
Lower greenhouse gas emissions. Solar thermal hot water is a fully renewable source of heating so can help to reduce your CO2 emissions.
Potential hot water benefit all year round. Solar thermal can provide 90 to 100% of your hot water in the summer months.

What are the downsides of solar thermal hot water?

The initial installation cost are high. Depending on the hot water system currently installed the price can be around £6000.
Solar thermal is very dependent on good weather. A period of cloudy or overcast weather can severely impact how much hot water is produced.
The winter is very poor for most solar thermal systems
Spring and Autumn have very variable solar thermal output.
Maintenance costs can be high. Solar fluid can be expensive and may have to be replaced at regular intervals.
The hot water is produced through the day. This may not suit your schedule

If you found this confusing:

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