Solar thermal energy systems principles

The solar collector is connected to a none-pressurized heat storage so that the water from the heat storage circulates through the solar collector. The water circulates from the bottom of the heat storage to the bottom of the collector, through the collector, then from the top of the collector to the upper part of the heat storage. We use a drain-back technique, ie, the water that circulates through the collector only circulates when there is enough solar energy gained and the collector is hotter than the heat storage. When the collector is cold, the water automatically returns to the heat storage so there is no danger of frost when the water remains in the collector. The solar collector also drain when the temperature of the collector is higher than 95 degrees C to avoid any danger of boiling.

Solar thermal energy systems with under floor heating

By using a double-jacketed water heater in addition to the solar thermal heat storage, the tap water will be re-heated in the top of the water heater, while water from the heat storage will circulate through the bottom of the water heater for re-heating before circulation to the under floor heating system. Note, that the water will only be re-heated if the solar heated water is not hot enough.

Solar thermal energy systems pressurized

The solar collector is connected to a separate drain-tank which now works as the none-pressurized storage and the water is circulated through the collector from this drain-tank. After the water is heated by the solar collectors, the water flows through a pipe heat exchanger in the pressurized tank so that the solar heat is transferred from the collector to the water in the pressurized storage. Then the water is pumped back through the collector.

1 - solar collectors

You can mount the solar collectors on the roof, wall or on a separate stillage. The solar collectors are designed to allow you to easily integrate them into the roof or wall on existing construction.

2 - solar heat storage

The solar heat storage is the storage tank to keep the heat from the solar collectors so that you can use the energy when it suits you. We have a solution for depressurized tanks and a solution for pressurized tanks. Basically, we recommend the solution for depressurized tanks as this will provide a less expensive solution and better transfer of heat to central heating.

3 - system device

The system device automatically regulates the operation of the collector based on the temperatures of the collector relative to the temperature of the heat storage. The system helps to automatically start and stop and secure the system against freezing and overheating. The system device starts at a temperature difference of more than 10 degrees in the collector relative to the heat storage, it stops at a temperature difference of less than 5 degrees and at 95 degrees C for the heat storage.

4 - circulation pump

The circulation pump circulates water through the collector when the system device signals to the pump to start circulating.

5 - 2-way magnetic valve

A 2-way solenoid valve is connected to the same signal as the circulation pump so that the valve closes the ventilation pipe when the pump starts and opens the ventilation pipe when the pump stops. When the valve is open to the air, the system will be drain and the water flows back into the storage. The valve should be normally open.

6 - throttle valve

For the collector to get the right amount of water, the solar thermal energy system is equipped with a throttle valve which ensures that it circulates around. 1 liter of water per minute per m2 of solar collectors.

7 - ventilation tube

The ventilation opens to air so that the solar collector drains when not operating.

8 - solar collector feed

The feed to the solar collector is in the bottom corner on the left or right side of the collector. The supply has a 15 mm diameter.

9 - solar collector return

The return from the solar collector is in the top corner on the opposite side of the supply. The return has a 15 mm diameter.

10 - flood tube

The flood tube from the solar storage ensures that the water has sufficient expansion opportunities when it is heated from cold water.