Installation of thermal solar energy

Solar power plant

Solar Heating Systems With Forced Circulation

In many cases it is not viable to install solar power equipment for the production of hot water thermosyphon, since often the location of the solar collectors is above the tank (for example, sensors on the roof and inside the accumulator & rsquo; housing, golf sensors, etc.)


In this type of installation, the water flowing between the collector and the accumulator can not do it by natural convection since warmer water (sensors) and is at its highest point and there is no natural force that makes displace the cold water that is already at the lowest point and is the heaviest.

So we must resort to a conventional electromechanical circulator, employees in heating circuits, in order to ensure circulation of fluid.

Circulator (pump) drives the fluid (usually from the bottom of the accumulator, cold zone) towards the bottom of the solar collectors.

Forced systems are always indirect, except uses of HVAC pool where you can use the drive system filter the water in the glass itself.

Basic elements of a solar system with forced circulation

The solar thermal installations with forced circulation, have the following elements:

Solar collectors: as in these assemblies the flow of fluid through the sensor is forced, pressure losses (resistance to the & rsquo; water) are not a major constraint in terms of value, since they can compensate the & rsquo; choose the circulator. What will be crucial is to know the pressure drop required to select the circulator.

In this type of & rsquo; facilities can use either vertical and / or horizontal sensors based on criteria of & rsquo; integration, even though the former have better performance.

Accumulator: This type of mounting allows use force to variations in the accumulator, since the circulator will pass the water exchanger incorporating or external exchanger for installations with high volumes of accumulation.

control system with forced circulation system

On computers with forced circulation, we must control the pump so that only drives the water at times when there may be energy gain (times do Sol and, therefore, the fluid temperature sensors exceeds the accumulator). The unit responsible for doing this is the differential thermostat that continually compares the temperatures of the sensor and the tank connecting or disconnecting the pump depending on what temperature is higher.

Security elements of a system with forced circulation

To protect the overpressure sensor is mandatory to install a safety valve (VS) in each group or row of sensors.

On the other hand, the primary circuit will be equipped with a security group consisting of at least: an expansion (VE), a safety valve and a pressure gauge.

Likewise, these facilities incorporate active protection systems against low temperatures (frost) or against high temperature (overheating).

Pump station

The movement group will generally be at the bottom of the accumulator (cold zone), towards the bottom of the collectors.

Y have the following elements:

  • Electromechanical Circulator for closed, the type used in heating circuits.
  • Check valve to prevent reverse circulation uncontrolled.
  • Flow regulator, which will adjust the flow of the circuit.
  • Filter, which will ensure the durability of the circuit elements.
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ICAEN - Institut Català d'Energia

Last review: September 23, 2015