Categories: Property

The pool-heating conundrum

&NewLine;<p><img class&equals;" alignright size-full wp-image-181" style&equals;"margin&colon; 5px&semi; float&colon; right&semi;" src&equals;"http&colon;&sol;&sol;schoolnewsnz&period;fastrackdev&period;com&sol;wp-content&sol;uploads&sol;2011&sol;10&sol;pool&lowbar;heating&period;jpg" alt&equals;"pool heating" width&equals;"200" height&equals;"150" &sol;>Ensuring that school swimming pools are warm enough for children to swim in&nbsp&semi;<&sol;p>&NewLine;<p> <&excl;--more--> <&sol;p>&NewLine;<p>has always been a problem in New Zealand where the warmest temperatures often occur when the pupils are on holiday&period;<&sol;p>&NewLine;<p>The ideal leisure swimming temperature is 25-27 degrees so it makes sense to maintain a pool at these temperatures when teaching children to swim&period; Most unheated pools are around 20-22 degrees for the majority of the swimming season&comma; so a heating system is required to achieve a comfortable pool&period;<&sol;p>&NewLine;<p>There are three types of heating systems&colon; solar&comma; gas and heat pump&period; Each has different characteristics which will affect their suitability&period;<&sol;p>&NewLine;<p>Consider the following&colon;<&sol;p>&NewLine;<p>1&period; Required temperature and length of season – some systems can achieve seasonal swimming only&period;<&sol;p>&NewLine;<p>2&period; Each pool is different – the geographic location has a big impact on what performance can be expected from a heating system&comma; as does indoor versus outdoor&period; Each pool has its own microclimate which will affect how naturally warm the pool is&period;<&sol;p>&NewLine;<p>3&period; Budget – each heating system will have a capital cost as well as an operating cost&period; Often the capital cost is not as important as the operating cost as the system is often paid for through fundraising or grants&period; The operating cost then has to come from the school&&num;8217&semi;s operating budget&period;<&sol;p>&NewLine;<p>4&period; Ease of operation – ideally&comma; any system should be easy to use&period;<&sol;p>&NewLine;<p><strong>Solar heating<&sol;strong><&sol;p>&NewLine;<p>There are two broad types of solar heating systems&colon; glazed and unglazed&period; Unglazed systems are predominately used for pool heating due to their lower installation cost&period; Unglazed systems are made from rubber or polypropylene&comma; with the latter being the longer lasting due to the increased UV resistance&period; Polypropylene solar collectors are generally more expensive than rubber systems&period; The disadvantage of unglazed solar systems is that they lose heat in windy conditions and do not perform in cold ambient temperatures&period; Glazed solar systems do perform in colder and windier climates&comma; but have a higher installation cost&period; The big advantage of solar heating systems is that they have next to no operating cost&period;<&sol;p>&NewLine;<p><strong>Gas heating<&sol;strong><&sol;p>&NewLine;<p>Reticulated gas heating systems are very reliable and can maintain a certain pool temperature year around if required&comma; although the operating cost is very high due to the cost of gas and the relative low efficiency of gas heating&period; Gas heating systems also have the advantage of being the fastest heating&comma; so can be used to heat a pool for short periods&period;<&sol;p>&NewLine;<p><strong>Heat pumps<&sol;strong><&sol;p>&NewLine;<p>Heat pumps used for heating pools in New Zealand are of the air source variety&comma; i&period;e&period; they extract the heat from the surrounding air using a compressor&comma; evaporator and heat exchanger to transfer it to the pool water&period; Heat pumps use a smaller amount of electricity &lpar;per kw&rpar; than the heat they extract from the air&period; This means they are more efficient than just heating a pool with an electric element&period; Their efficiency depends on the ambient air temperature&comma; so they are not well suited to colder environments&period;<&sol;p>&NewLine;<p><strong>Pool covers and rollers<&sol;strong><&sol;p>&NewLine;<p>Regardless of heating system&comma; a pool cover should be used&period; Approximately 70 per cent of a pool&&num;8217&semi;s heat is lost through the surface and a good quality thermal cover will retain much of this&period; Rollers play an important role in obtaining maximum life from the cover&period;<&sol;p>&NewLine;

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