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Solar Thermal

Benefits of SolarBenefits of Solar

The benefits of using solar energy for hot water heating are immense. For one the energy source comes for free and research shows that solar hot water heating systems can deliver up to 70% of the hot water requirements for an average household. Investing in solar energy is an investment in the future of the environment and should add to the resale value of your property. By using solar energy to heat domestic hot water you will be helping to reduce our dependence on fossil fuels while at the same time improving the energy efficiency, and potentially the value of your home. In particular solar energy scores positively with the new BER -Building Efficiency Rating scheme.

Solar Water Hearing System
UK/Ireland Solar Map

Solar Water Hearing System

System Design

The main components of a domestic hot water solar system are the solar collectors, water storage tank, solar controller and solar pumping station. The diagram on the right shows a basic concept layout of a solar hot water heating system. When designing a solar system it is imperative that the system is sized correctly; otherwise inadequate performance or overheating may occur. The following is the generally accepted best practice for sizing a solar system for the Irish and the U.K. climate.

Step 1 Calculate the household hot water usage 

Generally speaking the average daily hot water usage is between 40 -50 litres per person When sizing solar systems 50 litres is normally taken as an average.

Step 2 Determine location of collectors 

Ideally, collectors should be orientated due south if possible and at a pitch of between 40° and 50°. Variations to the optimum positions are permissible and the chart on the right shows the % reduction in solar energy captured. For example collectors facing due east at a 30° inclination will capture 80% of the maximum potential energy.

Calculate number of collectors requiredStep 3 Calculate number of collectors required

A solar system should be designed to cover the hot water requirement almost completely during summer months. As a rule of thumb approximately 1 m2 of collector aperture area is required per person.

Note if the collectors can’t be installed to optimum conditions the correction factors in the chart above should be applied. i.e. if the collectors are facing due east at a 30° inclination, then 1 m2 is multiplied by 100/80 = 1.2 m2.

Step 4 Determine storage tank size 

A general recommendation is to have 50 litres of water storage capacity for every m2 of collector aperture area. 
Recommended tank sizes for Firebird solar collectors are shown in the table below;

No. of Persons

No. of collectors

Tank Size (I)

2-4

2 x CPK-7210 Flat panels
2 x CVSKC - 10 Vacuum tubes
30 or 40 TZ58 Heat Pipes

200

5-6

3 x CPK-7210 Flat panels
3 x CVSKC - 10 Vacuum tubes
50 or 60 TZ58 Heat Pipes

300

 

What is solar thermal and is it right for me?

Underfloor heatingDuring daylight hours the sun’s radiation warms the earth, even when the sky is overcast. Solar panels can capture this energy and use it to heat water. Solar energy is an unlimited resource that produces no harmful emissions and requires no transportation or supply pipelines.

How does it work?

  1. Energy from the sun warms fluid in the solar collector panels.
  2. When the fluid reaches a pre-set temperature it is pumped to a coil in the bottom of the solar cylinder.
  3. The solar coil heats the cylinder water for domestic and occasionally heating use.
  4. If the cylinder’s temperature sensor detects that the solar panel has not collected enough energy to heat the water to its pre-set temperature, it allows the main heat source to top it up, (i.e boiler)