BAP is a innovative Canadian company with a revolutionary system of circulating the working fluid in solar water heating systems by means of a bubble pump. The system is revolutionary because the pump which is always required in frost-prone climates uses no electricity, has no moving parts, is self-controlling and yet moves the heated working fluid from the collector panels on the roof to the heat exchanger at the storage tank below.

Wilfred Sorensen invented the bubble pump in 1981 when he was practicing architecture in Kingston, Ontario. Research was carried out at Queen’s University Solar Calorimetry Lab with funding from the National Research Council of Canada. In 1978 unknown to Sorensen the US Department of Energy had commissioned the Franklin Research Institute to put together a team of experts to conceive ways to make pumping for solar water heating systems electric-free and self-controlling. Out of 21 possible solutions the one they gave the best hope for was the bubble pump.

BAP was incorporated in 1982 to carry on research, development and eventually to license or manufacture and market the pump. An early license agreement came to an end with the cessation of subsidies first in the US and then in Canada. Then the low cost of energy due to the recession of the 1990s devastated the solar water heating industry. BAP did manage to sell a few pumps mainly in the US in order to get feedback from do-it-yourself customers. Getting into production, however, was out of the question due to low energy costs and subsidies to the fossil fuel and nuclear industries.

Installation on House Roof

Today, with high energy costs and the certainty of global warming, the market for solar water heating has much improved. Having weathered the bad times and continued with research BAP is ready to expand production and share its technology with the world. There are many opportunities for those who are able to discard the old technology for the new. People around the world want hot water. When they come to know about electric free pumping, they will demand it. Only a tiny percentage of buildings in the world have solar water heating systems. We invite everyone to help us change the proportions so that only a tiny percentage of buildings do not have one.

Bubble Action Pumps Ltd. (BAP) is in the business of heating water using the energy of the sun. The business is located at Kingston, Ontario. Wilfred Sorensen is president and 90% shareholder. Our logo is at the right.

BAP was incorporated in 1982 (bus. # 128782) for the purpose of pursuing the business possibilities of an invention by Wilfred Sorensen, an architect in private practice at that time. The invention, US patent 4,552,208 was a circulating pump for active solar water heating systems where the water storage tank is at a lower elevation than the solar collectors. The pump is unique in that the sun supplies the energy required to push the heated working fluid down from the roof to the heat exchanger at the storage tank below thereby overcoming the density difference that attempts to make it stay at the top. Before this invention an electrical pump was the only means to cause this circulation. Videos of our pumps in action can be seen on our website


The market for solar water heating (SWH) is world-wide and increasing on account of global warming. A report by the National Renewable Energy Lab (NREL/TP-640-41157) states that solar water heating in the US alone could save 50 to 70 tonnes of GHG gasses. At present SWH accounts for heating only 1%. The example of Israel where all building must have solar water heating is happening elsewhere. Yet, with the exception of China, Israel and Greece most buildings are without solar water heating. The Paris Agreement to limit the rising temperature of the planet has resulted in subsidies to industries such as ours.

We shall focus our initial sales effort in areas that have the highest energy cost, good sunshine, and are easily accessible. While in areas where there is no danger of freezing, passive SWH systems will still be preferred on account of low cost. there are those who will pay more for active systems to avoid the sight of a storage tank on the roof such as is the case with passive systems.


Our circulation pump is low cost, simple, easy to install, self controlling, has no moving parts to wear and does not require electrical input or electrical permit. It weighs 1/5 that of an electrical system. Research at Queen’s University  showed that our system was 26% more efficient than electrically pumped systems. The bubbling action in the pump is visible and confirms that it is working


In common with all solar water heating systems (SWH) our chief competition in North America is the low cost of fossil fuels and especially fracking gas. The other problem in North America is subsidies to solar water heating that are available during the tenure of one government and withdrawn by the next. This causes stranded systems and dissatisfied customers.
Photovoltaic electricity is believed by some to be the future preferred system for heating water.  There are two reasons why this will not be possible given the 15% efficiency of PV to convert solar energy into electricity while conventional solar water heating captures 75%. The PV system would need to cost 1/5 that of a SWH system and would require 5 times the roof area, which is more than most houses have.