Heat pumps work in a similar way to an indirect solar system in that they heat glycol that heats more efficiently and that heats the water. A heat pump uses heat from the atmosphere combined with electricity to heat the brine, similar to the way an aircon unit works but in reverse.
So while electricity is used to heat water, less is required. However, it is dependent on electricity, which in Africa seems not to be a reliable power source and may become a luxury few can afford in years to come.
Heat pumps either have separate components, namely a storage tank and then a heat pump unit or can be an integrated unit where the tank and heat pump come as one item resembling a large space capsule. These are our preference as we have been advised that they are more efficient, quieter, and one could show it off to your friends…
A heat pump can also be connected to a solar system and would act as the ‘booster’. However, this requires considerable the initial capital outlay.
Heat pumps currently tend to be slightly cheaper than their solar counterparts as not as much capacity is required.
Both solar and heat pump systems are more efficient when placed in close proximity to use areas.
Many suppliers may recommend a ‘ring main’ system. This circulates hot water around the building constantly reducing the amount of time and water wasted when one opens the tap. However, this also requires water to be re-heated constantly as it losses heat while circulating and also needs power to pump it around constantly. It makes little sense to me in terms of power savings. If the ring main works on a timer system during peak periods it would make more sense to me.
With any system it is imperative that pipes are correctly insulated.
This post is a part of the ‘in hot water ‘series and should not be read in isolation.
Please see my conclusion on this issue of water heating.