Flat Plate Collector for Hybrid Heat Pumps

Flat Plate Collector is one of the components of hybrid heat pump water heater. Hybrid heat pumps are a combination of heat pumps and solar water heaters. So, a flat plate solar collector is there, which absorbs the sunlight, to produce hot water for your home.

In this blog, we will discuss in detail different aspects of a flat plate collector used in a solar heat pump. Let’s get started.

What is a flat plate collector?

It is a component used in hybrid heat pumps. The collector acts as a heat exchanger that converts the sunlight from the sun into heat to produce hot water. It is the component that absorbs solar energy, and then converts it into heat, which is further used to heat water.

Flat Plate Collector Working Principle

It operates by absorbing sunlight through its dark-colored surface, converting it into heat. Then it transfers the heat to the water stored, flowing through the collector’s tubes. The temperature attained by a flat-plate collector is of the range from 50°C to 80°C, depending on factors like sunlight intensity and ambient temperature.

Types of Flat Plate Collector

There are mainly two types of flat plate collectors:

  • Glazed Collectors
  • Unglazed Collectors
Types of Flat Plate Collectors. 1) Glazed Collector 2) Unglazed Collector
Do you know the Flat Plate Collector Types?

Glazed Collectors

Glazed ones have a transparent cover, usually made of glass or plastic, that protects the absorber plate and the fluid from the external environment. The cover reduces heat losses from the collector by creating a greenhouse effect, trapping the infrared radiation emitted by the plate. So, this makes glazed flat plate collectors more efficient and suitable for higher temperature applications, such as domestic hot water or space heating.

Unglazed Collectors

Unglazed ones do not have a transparent cover and are exposed directly to the ambient air. This means that they have lower heat losses than glazed ones. This is because they do not emit infrared radiation. They also have lower heat gains since they do not benefit from the greenhouse effect. Therefore, unglazed flat plate collectors are less efficient and suitable for lower temperature applications, such as pool heating or preheating water.

Flat Plate and Concentrating Collectors

Flat plate collectors are the most common type used in solar thermal applications. They have a large surface area to absorb sunlight and are typically mounted on rooftops or in open areas. On the other hand, concentrating collectors use mirrors or lenses to focus sunlight onto a smaller receiver, achieving higher temperatures but requiring precise tracking mechanisms to follow the sun’s path.

Difference Between Flat Plate Collector and Concentrating Collector

Aspect Flat Plate Collector Concentrating Collector
Design Large surface area, flat design Uses mirrors or lenses to concentrate sunlight
Temperature Moderate temperatures (50-80°C) Higher temperatures (above 100°C)
Tracking Mechanism Fixed installation, no tracking required Requires precise tracking to follow the sun’s path
Efficiency Lower efficiency compared to concentrating types Higher efficiency due to concentration of sunlight


A flat plate solar collector is a very important component of a hybrid heat pump. It helps in absorbing the sunlight. This sunlight is converted into heat to heat the water. Knowing about the collector will help you make the right decision. A solar heat pump is a big investment, so it is always better to know everything before you buy one for your home.

You can look for the Best Hybrid Heat Pumps at affordable prices at SolarClue®. SolarClue® is an online marketplace for solar energy products like Solar Street Lights, Solar Panels, Solar Inverters and many more. You can avail discounts up to 50% on the products.

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