Top Swimming Pool Accessories to Increase Value

Has your pool become boring and it has been weeks since you got into the water, or you feel that it looks too bland and could do with some accessorizing? SWFL pool construction experts say that accessorizing your pool adds value to the overall home price in addition to heightened pleasure at the pool. Before accessorizing, it is important to be aware of the regulations that apply. With that out of the way, what are some of the top accessories for your pool?

Robot cleaner

If you clean the pool yourself, it must be one pain you look forward to with apprehension. But there is no way out; the pool must stay clean. However, you can make this painless by letting a machine work for you. Automatic pool cleaners are typically designed to clean the floor of the pool but some models can work on the sides too.

Solar cover

SWFL spa construction experts say that installing a heating system in a pool is an expensive undertaking which can be avoided by installing a solar cover. The cover works by taking in the heat from the sun and retaining it, and directing it into the water. A solar cover can raise the water temperature by as much as 8°C. The cover has an added advantage in preventing water evaporation and reducing the need to top up and add cleaning chemicals. You will also save a lot in terms energy bills.

Slides and diving boards

Slides and diving boards add an element of fun to the pool by making different water games possible. Pool and spa construction professionals say that it is relatively cheap to install these features as you can get plastic slides and diving boards.

Swimming machine

Want to better your swimming skills? A swimming machine is what you need. This machine pushes water at you at different speeds. Some can stream over 1 million of water per hour.   A swimming machine gives an experience just like you would in a pool with larger dimensions.

Swimming pool lights

Make your neighbors envious with underwater swimming pool lights. Naples pool experts say that there are affordable fiber encased underwater lights that can be easily installed.   Lighting adds a huge aesthetic appeal to the pool. The pool can also be used even at night.

It is important to consider the dimensions of your pool before picking pool accessories. The shape of the pool must also be taken into account when placing your accessories. It is also highly recommended that the installation be done by pool experts.

House Too Small For a Pool?

Do you think your backyard is too small for a swimming pool? Naples pool construction experts say that it is possible to install a swimming pool in a small space with a good design. While a small pool may have limitation such as not being able to do laps, it is still a source of much pleasure for the family. How can you have a swimming pool in a constricted space?

Consult a professional

There are many considerations that go into building a swimming pool. Engineering and building codes have to be followed. Regulations on neighboring property, pool fence compliance and so on have to be followed. If you are building it indoors, it is recommended to have an interior designer have a say on how best to place the pool.

Decide on the building material

You can choose between fiberglass and gunite. Fiberglass pools are pre-fabricated and are easy to install. They are also cheaper than gunite. Naples spa construction professionals say that the spa seats in a fiberglass pool are more comfortable than the harder gunite. The main limitation for a fiberglass pool is that the fixed shape can make it impossible to install in irregularly shaped space.

Gunite is a mixture of sand, cement and water that makes especially hardened concrete. A gunite swimming pool can be designed in an irregular shape. This material will also last longer than fiberglass.

Measure for size

Building in a small space is tricky. The pool must be large enough to be functional and yet fit the space such that it does not dominate. The pool must also blend into place to fit with the style of the home.

The positioning of the pool must be done carefully. Ideally, you want the pool in a position that will get sunshine the whole day long. You will also have to consider the neighboring property.  An allowance of at least 1 meter from the fence is appropriate.

Our engineers work with CAD design programs in order to accurately design a pool thats just fit for you.

Accessorizing

The key to a beautiful small pool is well thought out designing. The space will limit any landscaping project. But you can still accessorize with underwater lighting. If the pool is outdoors, consider installing a solar cover which will save you money on energy bills and also provide protection. Get in touch with one of our engineers today and get started on your design.

Get inspired

SWFL pool construction pros say that there are many building magazines you can go through for inspiration. However, the best investment you can make when building a small pool is bringing in the experts. They will know the best pool to install in the small space available. Take a look at some of our job examples and get inspired.

Evaporation Study Compares Water Savings of Covers

Having a pool cover may save you money in the long run.

Results from a study performed in response to the California drought show that certain pool covers can significantly reduce water loss due to evaporation when they are in place.

Industry officials in the state expect the findings to help in its efforts to discourage restrictions that impede business, such as bans on filling and refilling and permitting halts.

The National Pool Industry Research Center compared the water loss in pools covered by various kinds of products, including solid track covers, foam covers, bubble covers, solar disks and liquid evaporation suppressants.

The researchers had two goals: Determine how much evaporation could be blocked through the use of covers; and compare the savings of different types of covers.

Several industry organizations participated in the study: The California Pool & Spa Association, the National Plasterers Council, the Independent Pool & Spa Service Association, the Association of Pool and Spa Professionals and World of Recreational Water.

Evaporation is a major factor in water loss and, conversely, water savings, the authors of the study report said. This especially holds true in warm-weather states such as California, where pools and natural bodies of water have been estimated to lose 50 to 80 inches a year to evaporation. The researchers estimated how much water could be saved among the state’s 1.18 million residential pools, which have an average of 430 square feet: If evaporation per pool were averaged out to 60 inches per year, then a 50-percent reduction in evaporation could save almost 9.5 billion gallons of water, they contend.

“Assuming average daily consumption rate of 100 gallons per person, the saved water would be sufficient to supply a city of over 250,000 people for an entire year,” the report said.

But various estimates before the study placed water savings from covers between 28 and 95 percent, so the groups hoped to attain a more specific figure.

The study was performed on test pools at NPIRC’s facility at California Polytechnic State University, San Luis Obispo. Each type of cover was applied to at least one pool on the premises, with another pool used as a control against which to compare the others. Cal Poly grad students monitored water levels once a day, usually between 7:00 am and 9:00 a.m., when winds tend to be calmer. Industry volunteers performed set-up and maintained the pools to ensure that the water complied with APSP standards. For the evaporation-reduction study itself, the pools were observed 65 days. To check for leaks, 11-day-long relative water loss tests were performed before the study began and after it was finished. When a leak was detected in a pool with one of the liquid covers, the study was extended four weeks so more data could be acquired.

The three highest performing covers fell within 1 percentage point of each other: Foam covers showed a 95.9 percent efficiency; bubble covers clocked in at 94.9 percent; and solid track covers at 93.9 percent. In the mid-range were solar disks, at 50.1 percent. The liquid evaporation suppressants rated lowest, between 14.4 and 15.8 percent.

The authors of the study report offered a caveat: Once installed, the covers remained in place throughout the study, except during cleaning and water level measurements. “In reality, the covers will have to be removed, possibly for extended hours, when the pools are occupied,” the study said. “This suggests that the efficiencies reported here for the solid covers should be considered as maximum possible efficiencies.”

They also reported unusually high winds and storms during the liquid evaporation suppressant tests, which may have had a negative effect on the products’ performance. However, a counterweight was presented by the lack of swimmers, which removed normal water disturbance from the equation.

The findings were encouraging to industry officials, particularly those with CPSA, who have been advocating for government agencies and water districts to require the use of covers in place of restricting filling, refilling and even permits as a way to combat the drought.

“It certainly shows the effectiveness of pool covers of different kinds,” said CPSA President/CEO John Norwood. “It’s our best way to contribute to conservation and various drought efforts. As we’ve talked to water districts about efforts of the industry to conserve, most of them have felt the idea of utilizing covers was the most effective thing that we could do.”

The association is planning a collaborative, multi-tiered campaign to get the information out. CPSA is prepared to contribute $10,000 and is looking for two or three additional organizations that can do the same.

Source: Evaporation Study Compares Water Savings of Covers| Pool & Spa News | Water Conservation, Association of Pool & Spa Professionals, California Pool & Spa Association, National Plasterers Council

RSPEC – Pool Evaporation Study – Outdoor

The leading cause for your pool to be losing water may be evaporation!

According to a study by the RSPEC (Reduce Swimming Pools Energy Costs) results show the evaporation does have a major role in water loss in pools.

1. INTRODUCTION

There are over 5.9 million heated swimming pools and spas in the U.S.1, consuming billions of dollars of energy annually. Because of this significant energy use, the U.S. Department of Energy (DOE) has launched a nationwide campaign to Reduce Swimming Pool Energy Costs, or RSPEC. Market ready energy efficiency and renewable energy products such as pool covers, solar hot water systems, and windbreaks will be supported through information and technology transfer to pool owners.

Pool owners must have reliable information about the cost effectiveness of potential energy efficiency investments. This requires accurate engineering methods to calculate pool energy loads before and after measure implementation. Evaporation is the chief component of energy loss in pools, so its prediction is very important. Energy analysts rely on methods presented in the technical literature, such as the American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) handbooks. However, there is significant disagreement in the results of various evaporation rate equations when applied to swimming pools.

Evaporation rate calculation disparities are primarily due to a lack of good experimental results based on pool direct water loss measurement. Therefore, DOE has sponsored a series of tests to measure evaporation and total energy loads in swimming pools. Tests have been conducted by the Solar Energy Applications Lab at Colorado State University. The background, procedures, and results of tests on a quiet, outdoor pool follow.

2. BACKGROUND

Measurements have been conducted by several investigators under controlled laboratory conditions of evaporation from pans or small tanks inside of wind tunnels2,3. Measurements of evaporation from lakes and reservoirs have also been performed to estimate losses to irrigation users3,4. These offer some information applicable to pools. However, water body geometry’s and surroundings differed from those of swimming pools, and they were unheated. In addition measurement accuracy’s were limited.

The widely used ASHRAE Handbooks5 have, for many years, contained an evaporation rate equation based on evaporation experiments, primarily those of Carrier2 as shown below:

2

W – evaporation rate, Lb/Hr-Ft.2
V – air velocity over water surface, MPH
Pw – saturation vapor pressure at the water temperature, in. Hg
Pa – saturation vapor pressure at the air dewpoint, in. Hg
Y – Latent heat at pool temperature, Btu/lb

The ASHRAE evaporation equation for undisturbed and actively used pools has been questioned on the basis of German investigations6,7,8. These reports show condensate collection from air dehumidifiers as functions of vapor pressure difference between the pool water and the air over a pool (the same form as the ASHRAE equation). They indicated that the quiet pool evaporation rate was about one half of the calculated ASHRAE values. Two concerns arise however with this assessment; the condensate collection from the dehumidifiers may not represent the total evaporation from a pool, and there are different coefficients used with the equation. Two of the papers use a coefficient 21 percent higher than in the ASHRAE equation.

Evaporation tests were conducted at Colorado State University during April of 1992 on an inactive indoor pool9. Evaporation rates during controlled conditions for eleven hours and more were 74 percent of that predicted by ASHRAE.

Outdoor pool energy estimates are available from Florida10 and Switzerland11, however they are based on few measured results. These studies took the total input energy to pools and attempted to analyze how this total would be broken down using heat transfer theory.

Outdoor pools are subject to greater evaporation, radiation, and convection heat losses than occur with indoor pools. A major difference is due to wind or air velocity as observed from the (A+BxV) component of the ASHRAE/Carrier equation.

Rohwer and others have developed wind velocity coefficients (B) from laboratory measurements. Figure 1 illustrates graphically the projected wind effects upon evaporation taken from six references. Even considering the lowest wind coefficients (the lowest slopes of the lines in Figure 1), it is clear that evaporation is some multiple of the static air condition due to normal wind levels.

3. OUTDOOR POOL EXPERIMENTS

The CSU study attempted to provide, for the first time, an evaporation rate prediction method based on accurate measurement of direct water loss, vapor pressure differences, and wind velocity, in an outdoor swimming pool.

3.1 Test Site

A neighborhood association pool with 4125 square feet total surface area and 144,000 gallons volume was studied. Buildings, trees, and fences were set back twenty or more feet such that the pool was well exposed to wind and solar radiation. Also most outward radiation from the pool was to the sky.

The pool water was circulated by conventional means through a sand filter, chlorinator and gas fired boiler for heating. The pool is maintained at 84oF by a thermostat in the return water line from the pool. Natural gas billing records indicated energy input to the pool was approximately 8 million BTUs per day without covering, and 5.5 million BTUs per day when covered for about 12 hours over night.

3.2 Methods and Procedures

Air and water conditions were monitored at six-minute intervals by a data acquisition unit, supplied to a desk-top computer. The computer provided real time output of the predicted mass evaporation using the ASHRAE equation and the corresponding drop in pool level.

Pool water temperature and air temperatures were measured with T-type thermocouple welded junctions. Thermocouples agreed to within .5 oF with a precision scientific mercury-in-glass thermometer and within .2 oF with each other. This precision includes the electronic signal conditioning and was repeatable during the testing period. Pool water temperature was measured throughout the pool volume several times during testing. There was no variation in temperature.

Air humidity was determined by monitoring the dew point temperature with an EG&G Model 660 dew point hygrometer. This instrument was calibrated just prior to testing to +/- .2 oC against a secondary dew point temperature standard. The combined accuracy of air temperature and dew point temperature measurement translates to approximately +/- 1.5 percent relative humidity.

The evaporation mass flux from a water surface cannot be measured directly by practical means. It must be measured by the liquid volume loss during the test period under consideration. At typical conditions in outdoor pools, evaporation rates of about .1 lb. of water per hour per square foot of water surface may be expected. At this rate, the water level in a pool will decrease about .02 inch per hour. With suitable equipment, water levels can be measured to an accuracy of +/- .001 inch, so the measurement of water level over a four-hour period can yield an accuracy within about three percent. Water additions and discharges to the pool circuit were prevented during the test period.

The pool water level was determined by a microtector gauge rigidly mounted to the pool side. This gauge has a high precision adjustment and senses electrical contact with the water surface. The level measurements were observed inside of a stilling well submerged below the surface, designed to suppress wave motion.

Wind speed was obtained from a rotating cup anemometer located at the edge of the pool one foot above the water surface. Two radiation sensors; an Eppley solar pyranometer, and a net radiometer were located on an extension arm over the pool. Radiation losses were computed as the difference between net radiation and the incoming solar radiation.

3.3 Outdoor Pool Testing Conditions

There is no practical way of controlling the conditions over an outdoor pool such that a single parameter, such as the wind, could be investigated. Consequently, numerous observations were recorded for entry into a spreadsheet format, so that the trends of interest would appear. Obviously more observations improve the confidence level of the results from this approach.

There was a limit to the number of observations possible because evaporation water loss is slow relative to the measurement techniques available, and also because there were no more than fifteen days available for testing. Most of the testing was conducted at night when the pool was inactive and the atmospheric conditions were steadier than in daytime. Night testing also improved the accuracy of total energy budget measurements by avoiding the influence of solar gain.

Testing periods of three hours duration and longer were desired. Winds were never steady for three hours, however, and the resulting averages seldom exceeded two miles per hour. Since the wind term in previous evaporation equations was linear, it appeared that averages were sufficient for the purpose of obtaining a wind speed coefficient. Higher wind speed points would add confidence to the results, however. Thus a method of greater precision in water loss measurement was sought to reduce the time period requirements for testing.

3.4 Evaporation Pan Measurements

Floating evaporation pans were introduced midway into the testing program to permit short term evaporation measurement. Two shallow aluminum pans, eight inches in diameter, were maintained approximately ten feet from the pool side by line and anchor. The evaporative water loss from the pans could be accurately determined at the pool site, by transfer of the water to a graduated cylinder. Typical water losses of 50 milliliters or more per hour could be measured to +/- one milliliter; hence an accuracy of within two percent.

The thin aluminum material of the pans insured temperature equilibrium between the contents and the pool water. A least squares straight line comparison of the pan measurements to the water level measurements showed a slope of 1.04, which means that pan evaporation rates were four percent higher than those in the pool. The cause of the small difference was not known, however it was consistent enough that pan evaporation could be used in short period tests by applying the four percent correction.

3.5 Evaporation Results

Twenty one evaporation test conditions provided sufficiently reliable results. The test periods ranged in length from 1.1 to 16.2 hours; the results are presented as hourly values for consistency. Evaporation water loss during short time periods under high wind conditions were obtained from the two pan measurements.

Winds for the outdoor test ranged between 0.3 and 7.2 miles per hour. Because there was no practical means to control either the wind or water vapor pressure difference under outdoor conditions, the test points are multivariant with respect to these parameters. To present evaporation as a function of wind, the form of the evaporation equation can be rearranged as follows:

3

Figure 2 presents a straight line fit to the test data for water evaporation rate per unit of water vapor pressure difference vs the wind speed. Figure 2 also presents a comparison of the test results with the two most applicable evaporation references; ASHRAE/Carrier and Rohwer. The test results yield coefficients of “A” equal to .068 and “B” equal to .032; or in the ASHRAE form of the equation:

4

or:

5

Also indicated in Figure 2 is the evaporation rate found in previous indoor pool tests9; .071 Lbs/Hr-Sq Ft-In Hg at .06 MPH “wind” speed. This is nearly identical to the .070 Lbs/Hr-Sq Ft-In Hg at .06 MPH from the outdoor test results.

Figure 3 presents the effect of wind velocity upon evaporation as determined by the above equation (V as MPH) for a set of lines of equal vapor pressure difference. Values of vapor pressure difference in the figure were selected arbitrarily. This form of presentation is intended to show the relative importance of wind in different climates or with hot water spas, for example.

4. CONCLUSIONS

The rate of evaporation from an unoccupied outdoor swimming pool is 16 to 28% lower than that predicted by the ASHRAE equation. In 21 closely monitored tests, at a pool temperature of 84 oF, air temperature of 58 to 82, and relative humidity of 27 to 65%, the evaporation rate was 76 percent of the ASHRAE value at no wind velocity, and 85 percent of the ASHRAE value at five miles per hour wind speed. A linear fit to the test data yields an equation in the ASHRAE form but with adjusted coefficients:

8

This relationship also conforms closely to results found earlier for the inactive indoor pool.

Radiation loss was approximately one-half as much as that due to evaporation. A correlation between radiation energy loss from the pool surface and temperature difference between the pool and air temperature was found for the range of conditions during testing. Heat loss by convection was approximately eighteen percent of total losses.

5. REFERENCES

1 “Swimming Pool and Spa Industry Market Reports”, National Spa and Pool Institute, 1987 and 1988.
2 Carrier, W. H. “The Temperature of Evaporation”, ASHVE Transactions vol. 24, p. 25, (1918)
3 Rohwer, D. “Evaporation from Free Water Surfaces”, Tech. Bulletin no. 271 US Dept. of Agriculture, 1931.
4 Meyer, Evaporation from Lakes and Reservoirs, Minnesota Resources Commission, June 1942.
5 1991 ASHRAE Handbook HVAC Applications, p.4.7
6 Biasin, Von K., and Krumme, W., “Evaporation in an Indoor Swimming Pool”, Electrowarme International, p. a115-a129, May 1974 (Germany).
7 Reeker, J., “Water Evaporation in Indoor Swimming Pools”, Klima & Kalte Ingenieur, no. 1, p. 29-32, January 1978 (Germany).
8 Labohm, G., “Heating and Air Conditioning of Swimming Pools”, Gesundheits-Ingenieur, p. 72-80, March 1971 (Germany).
9 Smith, C. C. “Measurement and Analysis of Evaporation from an Inactive Indoor Swimming Pool”, Report submitted to the U. S. Dept. Of Energy, Denver Regional Office, June 1992.
10 Root,D. “How to Determine the Heat Load of Swimming Pools”, Solar Age, , November 1983.
11 Guisan, O., “Thermal Analysis of Five Outdoor Swimming Pools heated by Unglazed Collectors”, (submitted August 1992 for publication in Solar Energy)
12 Bliss, R.W., “Atmospheric Radiation Near the Surface of the Ground” Solar Energy, Vol. 5, Nr. 103, 1961

Source: RSPEC – Pool Evaporation Study – Outdoor