GB2342958A

GB2342958A - Raising liquid using solar energy

Info

Publication number: GB2342958A
Application number: GB9918234A
Authority: GB
Inventors: Peter Mckay
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-08-04
Filing date: 1999-08-04
Publication date: 2000-04-26
Anticipated expiration: 2019-08-04
Also published as: GB2342958B; GB9816900D0; GB9918234D0

Abstract

An expansion chamber 31 has a solar collector wall 10 to which is bonded an evaporation screen 11 which holds and creates a large surface area of incoming liquid for evaporation by heat from solar radiation acting on the wall 10. Liquid in a reservoir 35 of the chamber 31 is forced past a non-return valve and is raised up an outlet pipe 32 by the vapour pressure, gaining potential energy, until the liquid level in the reservoir 35 falls to a level which actuates a float valve, allowing a cooling liquid to flow onto the evaporation screen 11, causing condensation of the vapour. The cycle is then repeated. The vapour system may be sealed, or it may alternatively vent to atmosphere.

Description

SOLAR POWERED PUMP The invention relates to a solar power pump that take its energy from the heat band of the solar spectrum. The embodiment of the invention in the description is a solar powered water pump, although the said pump could be used to pump other liquids or mixture of liquids that will evaporate and condense with in the working parameters of said pump.

Wind driven water pumps have long been used to raise and move water e. g. for irrigation in agriculture, for economic and environmental reasons renewable resources are desirable for this work.

An object of the present invention is to provide a method of moving water from a source to a higher level e. g. from an irrigation channel to a crop in a field.

The present invention obtains its energy from the same part of the solar spectrum as a water heater solar panel and would be a compatible pump for said heater panels, automatically starting, stopping and sensing the strength of the radiation without the need for electrically powered pumps or sensors.

With a very large array of the invention in the form of water pumps it maybe possible to construct a pumped storage hydroelectric generator for isolated dwellings in areas with predominantly clear skies.

According to the present invention, there is provided a solar powered pump with a solar collector that absorbs heat from solar radiation and converts it into vapour pressure, which pumps liquids to a higher level, with an arrangement of one-way valves and float valves that actuates a condensing phase and makes the process cyclical.

The invention will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a cross-sectional side view illustrating the flow of water and air through the gravity fed embodiment of the invention, Figure 2 is a detail sectional view, to a larger scale of the float chamber as shown in Fig. 1, Figure 3 is a side cross-sectional view illustrating the flow of water and air through the atmospherically sealed embodiment of the invention, Figure 4 shows the front view of the second embodiment with cutaway showing the water ducts and evaporation screen, Figure 5 illustrates a detail sectional view, to a larger scale of the front wall of the expansion chamber that also functions as the solar collector, and shows the distribution of water on the evaporation screen.

The solar pump illustrated in Figure 1 comprises an expansion chamber 31 the said chamber consist of an evaporation screen 11 which is bonded to the front wall 10 of the expansion chamber 31, the front wall 10 functions as the solar collector and would typically have a black pigmentation if made from synthetic plastics material or painted black on outer surface if made of thin sheet steel or aluminium, as shown in Figure 5 the evaporation screen 11 would typically be a very thin woven or fibrous material e. g. fibreglass, preferably the weave should allow the incoming water to run through the material at the refill phase, and then hold part of the water in the weave to create a large surface area at the interface between the water and the air in the expansion chamber 31.

As can be seen from Figure 1 and Figure 3 the back, top, bottom and side walls 14 are substantially lined with moisture resistant low density thermal insulation such as expanded polystyrene, this prevents heat loss during the expansion phase, and also prevents heat retention in walls at the condensing phase.

In the embodiment of the invention shown in Figure 1 there is a gravity fed input, at the refill phase the water flows down tube 19 through the open float valve 25 and then back up to the ducts 17 and then cascades down the evaporation screen 11 this effectively isolates the interior of the expansion chamber 31 from the heat source, the front wall 10 actuating a rapid drop in temperature and pressure inside the expansion chamber 31 causing most of the water vapour to condense out.

The incoming water flows on down the outlet duct 18 into the float chamber 27 until the inlet control float 23 closes the inlet valve 25 at the same time the pressure release valve 26 also closes, the small amount of water held in the evaporation screen 11 starts to heat up giving off water vapour this causes an increase in pressure in the expansion chamber 31, when the pressure is sufficient water in the float chamber 27 is forced past the non-return valve 21 and up the outlet tube 32 to a higher level than the feed level gaining potential energy.

As the air in the expansion chamber 31 becomes saturated with water vapour the pumping action slows down at this point in the cycle, the water level in the float chamber 27 as dropped causing the inlet control float 23 to drop leaving the bail valve 25 held in place by pressure, the pressure release valve 26 is integrally connected to the float 24 as the water level drops more, the mass of the float 24 overcomes the pressure and the pressure release valve 26 snaps open, releasing the saturated air to atmosphere via tube 20 and condensing coil 15.

The drop in pressure causes the inlet ball-valve 25 to open bring the cycle back to the refill phase, as the water runs through the evaporation screen 11 during the refill condensing phase the pressure in the expansion chamber 31 drops below the atmospheric pressure causing air to be drawn back down tube 20 into the expansion chamber 31 this continues till the water level in the float chamber 27 closes the pressure release valve 26.

If the pressure in the expansion chamber 31 falls below the atmospheric pressure whilst the two float valves are closed e. g. if cloud obscures the sun part way through a cycle, air will be drawn in through breather valve 22.

In the embodiment of the invention shown in Figure 3 the fundamental configuration is the same as Figure 1 the expansion chamber 31 has a larger internal volume integrating the float chamber 27 and a floating base wall 34. The said floating base wall 34 is made of the same insulating material as the side and back wall and floats freely on the water in the expansion chamber reservoir 35, producing a large area for the vapour pressure act on. Instead of being open to the atmosphere the said pump has a sealed vapour system. The gravity feed is replaced by a sealed container 29, at the refill condensing phase liquid is forced into the pump by atmospheric pressure through non-return valve 30, and up inlet tube 33, the expansion chamber 31 may need support struts for the front wall 10 (not shown).

This alternative form of the invention has the ability to pump liquid from below the base level of the pump and does not lose any vapour to the atmosphere.

Claims

CLAIMS 1. A solar powered pump comprising a container with one wall functioning as a solar collector, the said wall is thin and dark in pigmentation on the external surface and inclined at a suitable angle to collect solar radiation converting said radiation into heat, the heat is conducted to the inner surface of the solar collector wall, the said inner surface which is absorbent and holds a small amount of liquid in a film, the heating of said liquid creates vapour pressure in the container the pressure puts force on liquid in a reservoir connected to said container pumping the liquid to a higher level than the feed level, when the level of liquid in the reservoir falls a valve mechanism releases the pressure allowing liquid to flow into the container under the influence of gravity, cooling the solar collector wall, refilling the reservoir, and actuating a drop in temperature thereby causing the vapour to condense, completing a cycle.
2. A solar powered pump according to claim 1, wherein said valve mechanism releases the pressure into a sealed top reservoir the said sealed top reservoir is positioned above the level of the top of solar collector wall, the sealed top reservoir is refilled with liquid by the force of atmospheric pressure.
3. A solar powered pump according to claim 1 or claim 2, wherein said container walls are substantially lined with moisture resistant low density thermal insulation with the exception of the solar collector wall and the base wall, the said base wall insulation comprises a floating insulating wall the said floating wall floats freely on the reserevoir in the base of the container
4. A solar powered pump substantially as herein described and illustrated in the accompanying drawings.