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Solar Hot Water Systems (not PV)

The conventional polluting energy resources that our planet has provided are diminishing to a point where other methods of providing energy must be employed. Slowly international legislation is moving us towards using various alternative energy sources that are renewable and therefore have a lesser impact on our environment.  

 

The conventional polluting energy resources that our planet has provided are diminishing to a point where other methods of providing energy must be employed. Slowly international legislation is moving us towards using various alternative energy sources that are renewable and therefore have a lesser impact on our environment. 

Solar hot water systems sometimes referred to as Solar Thermal are systems that use the heat from the sun and transfer this renewable energy source through a heat exchanger into a water storage cylinder connected to it.

There are two types of unit:

A compact system where the storage unit is directly connected to the solar panel, these systems are passive and use gravity with the water circulating around naturally.

A split system where the storage unit is remotely placed away from the solar panel possibly in a utility  room or a garage circulation in this type of system is achieved by a pump.

 

Do you know how much DHW (domestic hot water) you use on a daily basis?

It is estimated that on average a family of four use 40-50 litres per person per day, this does not include washing machines or dish washers.

The technology to provide this amount of hot water is simple. Take a typical unit with 180L capacity. The heat exchanger a 2m square collector panel situated in direct sunlight (normally a roof installation) captures the suns energy through a series of copper tubes inside filled with a glycol/water mix. This fluid is the primary circulation part of the system it slowly heats up and transfers the heat into the storage cylinder connected to it.                

                                                

Water temperature.

The water temperature inside the storage cylinder gradually rises and can reach around 90c therefore when fully heated you have 180L of hot water available. Due to the high temperature of the water a mixing valve is needed to blend cold water with the hot bringing down the temperature at the taps in the home to approximately 60c. The mixing valve introduces 30% cold water with the hot stored water so in effect you have available 240L of water at 60c heated at no cost and achieved renewably by the sun.

Depending on the quality of the insulation on the cylinder once at full capacity the DHW stored can (without sun shine) remain at a usable temperature for showering etc. for approximately 48 hours. This time period will vary as the amount of hot water drawn off by individual family members will reduce the amount of hot water stored. However these systems are extremely efficient and their ability to recover temperature quickly is impressive.

Apart from the pump on the split systems there are no moving parts so maintenance is low these highly efficient systems constitute an ecological proposal and an effective energy solution, giving high output and reducing energy costs. They are easy to install particularly in new build but can be easily retro-fitted in existing dwellings. They are highly aesthetic systems, which can be simply and quickly installed to blend with the traditional or modern architecture of a building and to provide free hot water almost the whole year round.  

 

Fossil fuel back-up. 

Solar thermal hot water systems are as the name suggests solar dependant therefore they need a fossil fuel back-up, either electricity or gas. The sun does not shine every day even here in Spain.

With a typical installation of a mid-sized unit 150L capacity costing around €1800 the pay back (future energy cost savings versus initial outlay) period is short and savings will soon be made even quicker as fossil fuels and electricity prices rise. Electricity prices here in Spain are on average 25 cents per kilowatt hour, the fifth highest in Europe.

Based on a 50-80% cost saving against an electric hot water system most Solar Thermal manufacturers quote a 5 to 8 year payback period. 

Saving money and protecting the environment at the same time Come to Spain Group S.L. endorse all positive environmentally green technologies and initiatives.

Our property portfolio reflects this ethos with state of the art alternative energy technologies incorporated into the homes we offer our clients.

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