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How Do I Filter Water for my Heat Pump System?

C J Hiscock


How Do I Filter Water for my Heat Pump System?

How Do I Filter Water for my Open Loop Water Source Heat Pump to Prevent Blocking and Clogging?  The answer, of course, is to use a Rotorflush Self-cleaning Filterpump™ to deliver the flow and pressure you need to your heat exchanger. Why?

Because Rotorflush submersible filterpumps™ with integral self-cleaning intakes allow water to be pumped and screened at source, reducing the need for further filtration in your system and keeping water intake maintenance to a minimum. In addition, all our self-cleaning intakes can be used as eel screens, they are ideal for screening and protecting eels and elvers.  We can supply filter pumps that will meet Eel screening regulations for the flow rates your system requires.

What is an open loop water source heat pump system?

An open loop water source heat pump system extracts heat from open water, for example, from a river or lake.

There are two main advantages of these systems over closed loop systems. One is that there is usually far less excavation and pipework (and therefore less cost) required on installation. Two, water source heat pumps transfer heat at a higher rate than ground source or air source systems; this means that they produce more heat per unit of electricity used to run them.

The main drawback is that such systems are only viable where there is a ready supply of water that can be pumped into the system.  The water is pumped from a pond, river or lake through a heat exchanger that extracts heat from the water before it is discharged back to source.

Heat exchangers can be composed of many thin, slightly separated plates that have very large surface areas and small fluid flow passages for heat transfer, or comprise a series of narrow tubes.

The relatively slower uptake of open loop water source systems even at geographically suitable locations has in part been due to the concern that heat exchangers may block and clog with water borne debris.

Fortunately, this is no longer the case.

Innovation and Expertise

The continuing rise in the installation of heat pumps is driven as much by innovation and the increased efficiency of modern systems as it has been by the availability of grants and tax-breaks.

Prototype thermo-acoustic heat pumps, innovative sun coupled heat pumps and the development of dual source heat pumps demonstrate the speed of progress in renewable heating technologies.

Open loop water source heat pump systems have benefited in recent years from the originality and invention of the Rotorflush filterpump™.  They are the answer to the question ‘How Do I Filter Water for my Open Loop Water Source Heat Pump to Prevent Blocking and Clogging?’

The simple reason is that this innovative product or range of products combines a self-cleaning inlet filter and a submersible pump into an easily installed unit. These centrifugal submersible pumps have a built-in self-cleaning filter on their suction intake. Pumping and filtering are combined, and water can be screened without the filter or the pump or – crucially – heat exchangers becoming blocked.  The filter pumps self-clean with no loss or interruption of flow.

Installed in a lake, pond, or river, the Rotorflush will deliver a filtered output which thanks to the self-cleaning intake filter will run and run with very little maintenance.

Weed, leaves etc. are simply blown away from the filter screen allowing the pump to continue working uninterrupted supplying filtered water to your open loop heat pump. And these filter pumps are kind to aquatic life, protecting glass eels and fish fry from the pump intake.

These aren’t the coarse screens that you find on standard submersible pumps, but are fitted with filter mesh with apertures of 0.3mm so that your heat pump is kept running.

Water source heat pumps offer some of the highest performance coefficients of any systems, but until now have been considered less favourably than less efficient closed systems. This is because they are drawing water directly from the natural environment, a pond, river, lake or the sea with active ecosystems, whose main aim often seems to be to block up your system.

Rotorflush filterpumps™ require little maintenance, in most cases a yearly clean of the screen is all that is required.

There are many satisfied customers who have been using Rotorflush Filterpumps™ for years, and increasingly these innovative submersible pumps with integral self-cleaning intake filters are being used to protect open loop water source heat pump systems.

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