Solar Water Heat Collector comparison developmental tests.
To do a comparative performance study between an ISO accredited flat tube-fin type Domestic Solar Water Heat Collector and an unaccredited version under development.
For a DSWH collector manufacturer to have any such performance type testing done is a lengthy and expensive exercise which is seen as a stumbling block by such manufacturers.
For this reason, manufacturers tend to stick to existing designs and only concentrate on enhancing the effectiveness of these designs through more precise controls.
People want hot water in their homes. It must be available on demand, and the provision thereof must not add complexities to their daily lives. This is why electrically heated water will always be the more attractive option as long as the cost of operating such a system does not become inhibitive. After installing an electric water heater, normally totally out of view, it is usually forgotten about.
For any alternative method of providing domestic hot water to become widely accepted, it will have to offer the same type of “out of mind” simplicity and ease of operation, with cost being a major influencing factor. That is cost of the initial installation, as well as the average monthly running cost. These costs are obviously directly influenced by any investment made during development and manufacture of such a water heater.
The harvesting of solar energy to heat water for domestic use is not new. The majority of devices used and developed for this purpose over the years have been expensive and whilst technically simple, manufacturing them on a large-scale production have been intricate.
South Africa has 46 million inhabitants living in approximately 20 million domestic houses? Of which about 50% are owned by the inhabitants. The current installation cost of an appropriate all-electric system is in the region of ± R5000. These systems will usually last in excess of 20 years, needing only an occasional element or thermostat replacement of relatively minor cost implication.
The cost of high quality Solar Water Heating systems are typically around R35000. These are available as direct imports from Europe, America and Australia. These systems have been developed utilising the latest computerized system controllers and manufacturing techniques. The level of expertise required to install, service and repair these systems, in addition to the high initial cost is a further deterrent for being used in rural areas. However these systems are considered the benchmark in terms of performance, hence such a flat plate copper tube and aluminium fin collector coupled to a hot water storage vessel will be used in this comparative study.
The performance study will be an outdoor comparative study. Usually such a study relies on repeatable sun-days such that valid comparative tests can be replicated. This usually takes a very long time to achieve. To eliminate or reduce this problem, two test stands will be built whereupon the two systems for comparison will be mounted and tested. In this manner tests will be done simultaneously, hence the problem of replicating sun load, cloud movement etc, is eliminated.
The objective is not to classify the performance of the systems being tested, merely to see how they compare. It is envisaged that this method of testing may lead to the definition of a methodology for doing developmental testing, as opposed to doing testing for accreditation purposes.
Problems normally associated with conventional accreditation testing are:
1) High costs
2) Lengthy waiting periods due to scheduling at SABS testing facilities.
3) Lengthy test duration due to ambient and weather condition replication requirements.
To do a comparative performance study between an ISO accredited flat tube-fin type Domestic Solar Water Heat Collector and an unaccredited version under development.
For a DSWH collector manufacturer to have any such performance type testing done is a lengthy and expensive exercise which is seen as a stumbling block by such manufacturers.
For this reason, manufacturers tend to stick to existing designs and only concentrate on enhancing the effectiveness of these designs through more precise controls.
People want hot water in their homes. It must be available on demand, and the provision thereof must not add complexities to their daily lives. This is why electrically heated water will always be the more attractive option as long as the cost of operating such a system does not become inhibitive. After installing an electric water heater, normally totally out of view, it is usually forgotten about.
For any alternative method of providing domestic hot water to become widely accepted, it will have to offer the same type of “out of mind” simplicity and ease of operation, with cost being a major influencing factor. That is cost of the initial installation, as well as the average monthly running cost. These costs are obviously directly influenced by any investment made during development and manufacture of such a water heater.
The harvesting of solar energy to heat water for domestic use is not new. The majority of devices used and developed for this purpose over the years have been expensive and whilst technically simple, manufacturing them on a large-scale production have been intricate.
South Africa has 46 million inhabitants living in approximately 20 million domestic houses? Of which about 50% are owned by the inhabitants. The current installation cost of an appropriate all-electric system is in the region of ± R5000. These systems will usually last in excess of 20 years, needing only an occasional element or thermostat replacement of relatively minor cost implication.
The cost of high quality Solar Water Heating systems are typically around R35000. These are available as direct imports from Europe, America and Australia. These systems have been developed utilising the latest computerized system controllers and manufacturing techniques. The level of expertise required to install, service and repair these systems, in addition to the high initial cost is a further deterrent for being used in rural areas. However these systems are considered the benchmark in terms of performance, hence such a flat plate copper tube and aluminium fin collector coupled to a hot water storage vessel will be used in this comparative study.
The performance study will be an outdoor comparative study. Usually such a study relies on repeatable sun-days such that valid comparative tests can be replicated. This usually takes a very long time to achieve. To eliminate or reduce this problem, two test stands will be built whereupon the two systems for comparison will be mounted and tested. In this manner tests will be done simultaneously, hence the problem of replicating sun load, cloud movement etc, is eliminated.
The objective is not to classify the performance of the systems being tested, merely to see how they compare. It is envisaged that this method of testing may lead to the definition of a methodology for doing developmental testing, as opposed to doing testing for accreditation purposes.
Problems normally associated with conventional accreditation testing are:
1) High costs
2) Lengthy waiting periods due to scheduling at SABS testing facilities.
3) Lengthy test duration due to ambient and weather condition replication requirements.
G. Kleyn
28 January 2010
28 January 2010
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