Easy to Print SolaPlug Information
University of Ulster Test Report
| University of Ulster Test Report |
| Foreword |
| Solar water heating is a simple and reliable technology that
should be part of every home's heating system. |
| Containing the capital cost of a domestic solar installation is
the most obvious first step towards achieving financial payback in
its life time. |
| Retrofitting to the existing hot water cylinder probably offers
the greatest opportunity for reducing costs. |
| As with any system, the installer has a duty to communicate to
the customer the likely performance. |
| The University of Ulster have conducted a series of stringent
tests comparing the performance of the SolaPlug with the bottom coil
of a solar cylinder. |
| They used a 30 tube Thermomax collector to heat a 200litre solar
cylinder through the SolaPlug & bottom coil in turn. |
| Although 20 tubes would have presented a more favourable result,
we felt that it was important to use 30 tubes ( which is roughly
equivalent to 2 flat plates ) as it is a more common system size. |
| Summary |
| With 30 tubes & full strength sunlight, the SolaPlug was 4.3%
less effective at transferring heat to the cylinder than the solar
coil. |
| With reduced ( more typical ) radiation levels the results were
even closer. |
| The results confirm that for up to 30 tubes or 2 flat plates the
SolaPlug provides a well engineered and effective solution for
retrofitting solar. |
| Overall performance depends also on user behaviour, & boiler
heating timing. |
The experimental characterisation of the ‘SolaPlug’, a novel heat
exchanger for solar hot water application has been investigated under
controlled simulated conditions. |
 |
The performance of the ‘SolaPlug’ system has been compared with a
traditional twin coil cylinder.
The tests were conducted over four different test conditions including
(a) 6 hour constant 860Wm-2 with a 30 tube collector;
(b) 6 hour constant 459Wm-2 with a 30 tube collector;
(c) 6 hour constant 850Wm-2 with a 20 tube collector and
(d) standard draw-off condition. |
| The test was designed to compare performance under typical but stiff
conditions such as 30 tube as well as 20 tube collector, at high solar
input condition and the cylinder solar coil area of 1.64m². |
| Following the experimental investigation,
a number of important conclusions can be made with regards to the
performance and application of the ‘SolaPlug’ system. |
| Under low solar input conditions, the performance of the ‘SolaPlug’
system is marginally better than the ‘Coil’ system whereas the overall
system efficiency of the ‘SolaPlug’ system is slightly lower than the
‘Coil’ system while operating under high solar input conditions. This is
due to the reduced performance of the collector at higher collector
inlet temperatures exhibited by the ‘SolaPlug’ system. |
| When tests were conducted using a 20 tube collector at a constant
850 Wm-2, the ‘SolaPlug’ system shows marginally better performance than
the ‘Coil’ system indicating the importance of collector/heat store
sizing. . |
The ‘SolaPlug’ system heats the upper volume of the store at a
higher rate than the ‘Coil’ system.
The average temperature in the upper half of a cylinder for the
‘SolaPlug’ system is approximately 9 to 12% higher depending on the test
conditions. |
| In terms of overall average storage temperature, both systems
perform in a similar fashion with only a 1-2?C difference in
temperature. |
| Under a typical domestic hot water demand, the ‘SolaPlug’ system
delivers water at higher temperatures than the ‘Coil’ system, supplying
a superior solar saving fraction (SSF). |
| The heat exchanger rating of the ‘SolaPlug’ unit was 223 W/K. |
| The full report can be read or downloaded via the link below |
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