motel owners
Journal
THE AUSTRALIAN
Swimming pools and spas
PAUL WERE I Dontek
Inviting Swimming Pools and Spas are an attractive way for Hotels and Motels to entice new patrons and to
keep existing ones. Although an inviting pool or spa may look great, the water temperature must be set to a
level where the experience meets expectation, but which one to get?
POOL AND SPA HEATING OPTIONS
A
s there are many options in heating a swimming pool or
spa it is advisable to contact a pool heating specialist and
have a heat load evaluation to find the most economical
and environmentally friendly system. The most common options
currently available are:
Solar
Solar Heating
Gas
Gas Heater
Solar is an extremely economical way of heating a pool and has
a relatively low capital cost. Water is pumped from the pool to a
heat collector fitted to the roof that absorbs radiant energy from
the sun and returns to the pool. This heat collector can be made
in many different styles; some are made from extruded PVC Nitrile
or EPDM rubber strip, moulded tube panels, glazed poly panels
and more. When year round heating is required a backup system
such as Gas or Heat pump is required.
High Efficiency Solar
Gas has traditionally been the most common form of pool heating
as it is easy to install, has a low capital outlay and can provide
rapid heat up times. The heater usually has pool water pumped
through a Heat Exchanger which sits above a gas fired burner
tray; this heat is transferred to the water and returns to the pool.
Newer style gas heaters utilise fan assistance that aids in the
combustion and heat transfer process that increases efficiencies
and reduces operating costs. A gas heater is an ideal stand alone
system when natural gas is available or the perfect back up for
Solar or Heat Pump systems.
High Efficiency Solar
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motel owners
Journal
THE AUSTRALIAN
High Efficiency Solar uses Glass Evacuated Tubes to collect the
heat. A number of systems are available; some are even used in
conjunction with heat exchangers and shared with the potable
water system. This is a very economical system to run and
although capital cost appears high, it can be amortised over
the two heating systems. A backup system is normally required
to guarantee a suitably heated pool.
SMART HEATING CONTROL ELECTRONICS MEANS
MAXIMUM EFFICIENCY
Heat Pump
When a gas system is utilised, electronics can be used to
accurately control run times, set temperatures and heater cool
down times. This ensures energy is not wasted from slow
switching mechanical thermostats or thermostats that are fitted
within the heaters high temperature cabinets. Peak swimming
times are also allowed for.
Even the most economical heating systems for pools and spas
can require a back up system and this is where a digital control
system can pay dividends. The controller will monitor the most
economical way of heating and will switch between heat sources
as required.
On Solar Systems the controller will monitor the pool temperature
and when heating is required will turn the solar system on if
there is solar gain. When auxiliary heating is installed – normally
gas or heat pump fitted in conjunction with solar – the controller
will determine which heat source is best to use. If heating
is required the controller will check solar temperature and if
insufficient, it will switch on the auxiliary heater and it will run
until the set limit is reached or until there is sufficient solar gain.
If solar gain is insufficient for the water temperature to reach the
limit, then both heat sources will run concurrently. When there is
enough solar gain to achieve limit the auxiliary heating will be
turned off and only the more economical solar heat source will
be utilised.
Heat Pump
Heat Pumps have become more common for heating as capital
costs have been reduced over the past few years. They can be
used as a stand alone system as long as heat load calculations
have been performed correctly. Heat pumps are least efficient
during the coldest months and it is common practice to have
a gas heater as back up for prolonged cold spells.
Heat pumps work like a reversed air conditioner. Instead of taking
air from a room or building, removing the heat and returning it,
a heat pump takes large quantities of air from the atmosphere,
removing the heat contained in the air and transferring this to
water from the pool or spa passing through the unit.
The characteristic of the heat pump of absorbing heat value from
air means that the unit has a low electrical input relative to its
heat transfer. A well designed heat pump will output heat at a
rate of around 5:1, relative to its energy input under summer
conditions. This greatly reduces total energy consumption.
This factor is called the heat pump’s co-efficient of performance
or COP.
The capture of solar energy from air means that the heat pump’s
output and efficiency will vary with air temperature. Higher
efficiency is gained in more temperate locations but heat pumps
are capable of maintaining pool temperatures year-round in nearly
all areas of Australia and New Zealand.
When Salt Chlorinators are used in multiple or smaller systems,
over Chlorination is common as the Filter pump may run for
extended hours to keep the Heat Pump going. The controller will
turn the Salt Chlorinator off when extended heating times are
required, or an electronic monitoring system should be fitted.
HOW TO SAVE ON RUNNING COSTS AND
THE ENVIRONMENT
When multiple heat sources are utilised it is imperative to set
the most economical heat source to a higher temperature setting
than the auxiliary temperature setting. Consequently, the cheaper
heat source will push the water temperature above the auxiliary
setting therefore minimising the auxiliary source’s run time. The
greater the temperature difference between the two settings
the larger the savings will be. What needs to be considered
are the minimum and maximum temperature settings that are
comfortable for the user. Commonly used minimum and maximum
temperatures are 26 degrees Celsius and 29 degrees Celsius
respectively, however, this will differ from State to State as pool
temperature needs to be set relevant to ambient air temperature
to achieve a comfortable level.
73
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