English Instructor Manual (PDF) - Metric Version - National ...

Briefl y discuss the three advantages heat pumps with scroll compressors
Defi ne coeffi cient of performance
Activity: Using Appendix J - Calculation Formulas, do several heater sizing calculations.
Key Points: Discuss ways to prevent energy loss. These include:
In outdoor pools, shelters such as trees, fences, plants, etc. help reduce convection and
evaporation energy loss due to wind.
In indoor pools, control air-to-water temperature differences. To keep heat in the water,
the air temperature should be between 1°-2.5°C warmer than the water.
In indoor pools, control relative humidity. Relative humidity should be maintained
between 40% to 60%.
Covers reduce the loss of energy due to convection, radiation, and evaporation by about
50% to 70%.
Key Points: Explain that, for indoor pools, proper air circulation is as important as proper water
circulation. For example, during breakpoint chlorination, waste and by-product gasses evaporate
into the air directly above the water. If poor air circulation does not remove these gasses, they will
dissolve back into the pool water, drastically increasing the combined chlorine levels of the water
and making the breakpoint chlorination process useless.
Discuss the considerations for designing proper air circulation. These include:
Humidity control.
Ventilation requirements for air quality (outdoor and exhaust air). Be sure to follow the
ASHRAE requirement of 2.4 litres per second per square metre of pool and deck area
Air distribution.
Air duct design.
Evaporation rates.
Pool water chemistry.
Key Points: Discuss the operation recommendations for air control systems. These include:
Maintain relative humidity between 40%-60%. Less than 40% makes the air too dry
and increases evaporation. More than 60% encourages condensation and corrosion
problems.
Maintain the air temperature between 1°-2.5°C greater than the water temperature.
Air velocity should not exceed 0.13 metres/second a point 2.4 metres above the walking
deck. Any faster creates a “breeze” that may cause discomfort to swimmers. Any slower
will not be suffi cient to remove waste and by-product gasses.
Since re-circulated air contains waste and by-product gasses, suffi cient outdoor air must
be mixed with the indoor air to keep it fresh. Most recommendations suggest at least
a 50% mix of fresh air and recirculated air. When outside temperatures allow, 100%
outside air is preferred.
The entire volume of air should recirculate four to six times an hour.
Recommend that students enroll in and take the Indoor Air Quality online course from
NSPF.
Final Questions: Ask the participants if they have any questions pertaining to the lesson they
have just completed. If there are participants who are still having trouble with the concepts of this
lesson, offer additional help during a break or after class.
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© 2014 National Swimming Pool Foundation®