A New Low-Cost Plastic Solar Collector

An innovative solar collector based on a long plastic hose that is connected directly in series from the district water grid to consumption is presented. It takes advantage of plastic tubing to develop a simple self-construction collector that costs about 70 dollars for a one-family unit. In addition, due to its solar-pond configuration, it could achieve a good thermal performance, as it was demonstrated by modeling. 1. Introduction The photovoltaic panel is the preferred renewable technology to obtain electricity from homes in developed countries, but regarding new high-efficiency home appliances this consumption is expected to decrease in the future. On the other hand energy consumption for heating water will remain unchanged considering that domestic heaters have reached their ideal efficiency. Although this represents only 15% of the total household energy demand in cold-climate developed countries, it increases up to 40% in developing countries with temperate climate and even more in poorer tropical ones. This is contradictory; whereas solar collectors have a large market in developed countries, this is minimal in developing ones. This discrepancy has a correlation regarding the evolution of solar technology which should be studied considering that solar collectors produce energy five times cheaper than PVs [1]. It is well known that a small solar collector based on modern vacuum tubes (2-3？m2) can satisfy the one-family demand anywhere. This design is more suitable for cold high-latitude locations than flat collectors since its cylindrical shape receives almost twice as much solar irradiation [2] and minimizes heat losses as well. Nowadays more than 90% of the worldwide market is supplied by Chinese manufactured vacuum-tube collectors with final prices as low as 500？USD in developed countries with large solar markets. On the other hand the scenario is quite different in developing countries. Due to the small size of the market in these countries, prices generally exceed the previous level by far. Actually, prices are double or more in origin due to the low scale of trading involved, and the final price paid by users can be even higher because of the following.(1)Freight cost within the country adds up to 200？U$D. Many developing countries are large with low-population density and a weak transportation infrastructure, so freight costs for fragile devices are usually high.(2)Costs of installation add up to 400？U$D. A large country with small market and weak dealer’s network is a big drawback; in this sense the complexity of the heat-pipe technology