TECHNICAL DATA
Product Analysis*
Enviro Window Insulators’ energy saving attributes were tested in South Africa by the Engineering Faculty, North West University during June/July 2008 – research leader Professor LJ Grobler.
Some of the Product Trials in South Africa:
Actual electricity savings were tested by North West University in offices containing installed air conditioners. The research team is available to explain test methodology and answer any technical questions. Additional testing can be arranged on request.
Three offices, ordinary and not north facing, were instrumented:
1. Fitted Blinds plus Enviro Window Insulator
2. Hanging Blinds plus Enviro Window Insulator
3. Control Office – no Enviro Window Insulator
The AC units were set at 24˚C and set to operate 24 hours of the day. Measurements were taken every 10 minutes and integrated to an hour. Measurements used for this analysis were for the periods 27-28 June and 1-3 July 2008. Measurements were taken of the following parameters every 10 minutes.
i. Room temperatures
ii. Outdoor temperatures
iii. Power consumption of AC units
The table below shows the results of this trial. The two offices fitted with Enviro Window Insulators together with hanging or fitted blinds used between 25 - 35% less energy than the standard office. The difference in savings as shown in Table 3 is explained by the existence of a sky light in the office in which the lower (25%) savings were achieved. Windows of test offices face south east. No direct sun on windows.
Table 3: Results of North West University Trial (Electricity Savings per day)
1.1.2 Solar Gain and UV Blocked
Using EDTM Solar Transmission and BTU Meter equipment , single pane, double pane, and low E windows with and without Enviro Window Insulators were compared. The EDTM glass testing equipment (EDTM is a US National Fenestration Rating Council certified manufacture of glass testing equipment) enables 3 important effects to be demonstrated:
(1) How much heat passes through different types of glass,
(2) How much heat passes through the Enviro Window Insulator.
(3) How window efficiency is improved with Enviro.
In addition, the Enviro Window Insulator alone was also tested. The equipment was calibrated where the heat measured at the meter was at 100%, each piece of glass was positioned between lamp and the meter and the metered results recorded. The results of this test showed the following:
(Please click on images to enlarge)
With a single pane clear, 85% of the heat (BTUs) passed both ways through the glass, double clear pane allowed just more than 70% of the heat to pass both ways through the glass, and double pane low-E allowed 61% of the heat to pass both ways through the glass. The tests were repeated to measure the reduction in the percent of heat that passing through each type of glass when the Enviro window insulator was positioned between the testing solar meter and the different types of glass. Single pane clear showed a reduction to 17% of the heat (BTU’s) passing both ways through the glass with double pane clear showing a reduction down to 20%. Double Pane low-E: showed a reduction from 61% of the heat passing both ways through the glass down to 17%.
With the meter calibrated and registering 100 % of the heat recorded at the meter, the Enviro Window Insulator was placed between the source of the heat and the meter in the same placement as the glass samples. The test results reported that the Enviro window insulator reflected 72% of the heat passing through the window. The above tests clearly indicate that when the window insulator is added as an interior attachment to windows the heat that passes through the glass will be substantially reduced.
Similar tests were then conducted for UV rays which cause much damage to curtains, carpets, and furniture. The results were as follows:
(1) 1-0D784-85-00
(2) BTU - British Thermal Unit, the unit of heat in the imperial system, is the amount of heat required to raise the temperature of one pound of water through 1oF (58.5oF - 59.5oF) at sea level (30 inches of mercury).
- Btu = 1055.06 J = 107.6 kpm = 2.931 10-4 kWh = 0.252 kcal = 778.16 ft.lbf = 1.0551010 ergs = 252 cal = 0.293 watt-hours
- An item using one kilowatt-hour of electricity will generate 3412 BTU
(3) Btu Power Meter Model # 2065
(4) Low Emissivity
Electricity Savings Calculation
The “Energy Savings Calculator” which was developed in order to assess the impact of the window insulator on heating and cooling costs. This tool can be customized for the particular circumstances for each customer can determine the energy savings per annum, by taking specific calculations into account using the real glass used and façade orientations. The customer can hence determine the payback after installation of the insulators. The model also allows the calculation of the reduction in CO2 emissions.
Brief explanation of methodology: The energy savings calculator only takes the energy flow (meaning solar heat gain and thermal heat loss) through the fenestration[1] into account. It assumes that all gained solar heat (due to radiation) has to be cooled down and all heat loss has to be compensated by heating. The calculator takes only the "fixed things" into consideration: glass type, shading, m² of glass and geographical position.
Based on data collated from international databases over several years, the solar irradiation and average temperature for each geographical position is known. Based on these figures, the difference in energy flow with or without the window insulator can be calculated. The calculator takes into consideration the maximum amount of sun entering the building on the north facing façade through the g value (solar coefficient) which measures the solar heat gain through the window.
(1. i.e. all gained solar heat through walls, doors, ceilings etc. are not considered. In addition, the internal heat load due to people, lighting, computers etc is not within the scope. All these variables are different per building and use of the building.)
We are active in every province of South Africa. Our installation teams will do all installation either under our personal supervision or under the strict supervision of selected installers. For more information please contact us. We are increasingly receiving enquiries from energy consultants & Governments of various African countries
Ongoing research & tests by the University of North West School of Engineering as well as other reputable universities, are in process. All technical data are verified by Eskom.
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