Date Submitted:		March, 1996
Prepared on Behalf of:		Flexible Solutions Ltd.

Topic:

Effects of 'HEAT$AVR' on Evaporation and Heating Requirements in Indoor Pools

Introduction

Water evaporation is undesirable in indoor pools because it results in excessive humidity in the pool building, because the evaporation process affects water-chemistry, and because evaporation consumes much of the energy used in heating the pool. (Each liter of water evaporated consumes 2268 kJ of energy).

heatsavr is a pool additive marketed by Flexible Solutions of Victoria, B.C., that covers the water surface with an organic mono-molecular film. The claimed effect of heatsavr is that a small daily addition of 0.6 mL/day is sufficient 'to reduce evaporation from the pool surface, which in turn reduces the energy requirements for heating.

Carmanah Research Ltd. was contracted by Flexible Solutions to undertake an independent evaluation of the efficacy of heatsavr in reducing evaporation and heating costs in indoor pools. This report presents the results of two laboratory experiments conducted between 22 January and 9 February, 1996, with spa-sized pools in Carmanah's laboratory.

Experimental Design

Experiment #1:
Comparison of Treated and Control Spa

This experiment compared the evaporation and heating requirements of two identical spa pools, one a control and one treated with heatsavr. The internal size of the sea pools was approximately 182 cm diameter, the surface area was about 2.6 mE, the maximum depth was about 70 cm and the water volume was approximately 800 L (see Figure 1). The spas were manufactured by Pacific Spa, Langley, B.C., model number N48AC21 0BOC, 1.5 kW heater, 1.0 hp pump and a rated amperage of 16 amp. The current draw of each heater was 13.2 amp, confirming that the wattage of the two heaters was identical.

Each spa was adapted so that its heater and pump turned on simultaneously and a meter was installed in each spa to record its 'on' time. The electrical supply to the units was identical, to ensure identical supply voltage. The spas were located in a laboratory area, immediately adjacent to each other, with virtually identical surroundings, although the room geometry precluded making the surroundings completely identical.

The spas were set up at identical operating temperatures of 28.5 +/-0.5°C and allowed to stabilize for a period of a week. The air temperature was kept at about 22°C for most of the experiment. Preliminary experimentation showed that heatsavr needed to be added in unusually high quantities initially (30 mL per day) apparently to saturate the spa filter. After the first three days, the amount of heatsavr added was reduced to 5 mL per day (about 2 mL/m2).

The air and water temperatures were monitored each morning (8 AM) and evening (4 PM). heatsavr was added each morning. To replace evaporation, water was also added to the pools each morning to keep them at a uniform depth. The pools were operated without covers, and the air temperature was kept at 220 C as nearly as possible, although some nights the heat did decrease to about 16oC.

The experiment was conducted over an 11.3 day period, and the total heating requirement of the spas was determined and compared. The amount of water evaporated from each spa was also determined, as was the relative humidity above each spa.

Experiment #2

The second experiment utilized only one spa: the control spa from the first experiment. This experiment was intended to confirm that the heat savings noted in the first experiment were not attributable to differences between the two spas. Accordingly, the control spa from the first experiment was treated with, heatsavr and the heating and evaporation data were compared with the results obtained on the same spa in the first experiment. After a break-in period to saturate the filter, this spa was treated with 5 mL of heatsavr per day for a period of 4.33 days, and the energy consumption for heating and the evaporation were monitored. The resulting data were compared with the data from the control spa in the first experiment.

In the second experiment, heatsavr was added to the control spa. This experiment compared the same spa (the control spa) before and after heatsavr addition.

Duration of experiment:
The data from the first experiment for the control spa was compared with the data from a 4.33 day experiment with heatsavr added.

Energy consumption for heating:

Evaporation: