The ShowerPowerBooster pump started life as a solar thermal pump working off a 12 volt battery re-charged by a solar photo-voltaic panel to boost pressures in a solar thermal system in Norwich. The power of the pump was increased and it is now fully commercialised, making it perfect for showers and taps, but it still retains the features which made it perfect for solar thermal applications.
In order to evaluate a pump, it is useful to compare a product with the market leader for boosting solar thermal, and in Portugal this market leader is the Grundfos.
The market leader in Portugal is the Grundfos UPA 15/90, which is a much larger pump than the SP2B. The practicalities of fitting it in a pipeline are less than ideal, as at 2.5 Kg pipe supports are required. It cannot be fitted pumping downwards, which is unfortunate, as water pipes from a tank on a roof need to fall downwards to feed a home (although you could modify the pipework to run horizontally to fit the pump, but not on the roof).
The SP2B is much lighter at 0.18 Kg (0.625 including brass fitting), and can be fitted in any direction. It can be supported by the existing pipework without modification and can be fitted on the roof.
The SP2B is designed to be fitted on the roof. They are fully waterproof; the pumps are protected by stainless steel filters; and low voltage leads assure that the electrical installations are safe and resilient even in wet and windy weather. The pumps include 22mm compression female to 3/4 inch female adaptors, manufactured exclusively by Flowflex Components for the SP2B, to enable the SP2B pumps to be integrated into any pipe arrangement on the roof, including connections to galvanised iron pipes.
The possibility of running the Grundfos UPA 15/90 off-grid using solar PV is more difficult, as it draws up to 118 watts, as opposed to 12.5 watts for an SP2B.
The literature claims the UPA 15/90 can be installed directly on the incoming water mains ‘provided approval has been obtained from the local Water Company’. If the UPA 15/90 were fitted on an incoming water main it would breach the UK Water Regulations in the UK by a very considerable margin, as the pump pumps 25 litres a minute at maximum output, which is twice the 12 litre a minute limit. I cannot imagine any Water Company giving approval to fit a UPA 15/90 on an incoming water main, and if it were fitted it would present a serious contamination issue due to potential depressurisation of the main.
The SP2B is legal and does not require approval.
The UPA 15/90 literature states:- ‘To avoid cavitation noise and risk of damage to the pump bearings, a pressure of minimum inlet pressure of 1.5 m head (0.15 bar) is required at the pump during operation.’ This makes the UPA 15/90 unsuitable for boosting water from roof top tanks on the roof unless the tanks are elevated at least 1.5 metres above the pump. The pipework in a home below the roof could be re-routed to allow pump installation, but since the pipework is often encased in concrete in Southern European homes, this could be impractical.
The SP2B will never cavitate and needs a minimum inlet pressure of 0.1 metres head, so it can be fitted on the roof.
The maximum temperature of the UPA 15/90 is 70 degrees centigrade, making it unsuitable for boosting solar thermal heated water. The SP2B will endure sustained temperatures of 85 degrees centigrade and will tolerate temperatures up to 100 degrees centigrade, making it perfect for vented systems.
The UPA 15/90 is rated IP54, which means it is not waterproof.
In Cyprus the installers pointed out that the pumps that they had fitted to solar syphons in the past failed quickly and often within 6 months of fitting, which was why they were impressed by the 3 year SP2B warranty.
The UPA 15/90 has a 1 year warranty and for reasons of the need for a minimum 1.5 metres head on the inlet during pumping (perhaps 2 metres static head), and the 70 deg c maximum temperature, the normal and obvious places to fit the pump on the roof are unsuitable and would invalidate even the 1 year warranty.
The pipework within many Southern European countries is encased in concrete once it leaves the roof, so where I would fit the UPA 15/90 is a difficult question.
The UPA 15/90 appears unsuitable for boosting hot water from solar syphons in most homes; however, it is the market leader for boosting hot water from solar syphons in Portugal.
The source of the data I quote is:-