Environment


Keeping the Eco-friendly concept on the top motto, we have taken a step ahead to manufacture the Eco-friendly Kraft paper based Evaporative Cooling Pads.

Evaporative Cooling

In India in most of the states, temperatures can easily exceed beyond unbearable circumstances. Such high temperatures reduce crop quality and worker productivity. Evaporative cooling is the most common method for reducing the temperature inside a premise. Air conditioning or refrigeration systems can be used, but their installation and operating costs are usually prohibitive. Evaporative cooling is an economical & environment friendly process that reduces air temperature by evaporation of water into the airstream. As water evaporates, energy is lost from the air causing its temperature to drop.

The basis of any evaporative cooling system is the evaporation of water into an airstream. The most common way of accomplishing evaporative cooling in a greenhouse is with a fan and pad system. Exhaust fans with boxes, shutters, and guards (space 20-30 ft apart)

FAN & PAD EVAPORATIVE COOLING SYSTEMS

Fan and pad systems consist of exhaust fans at one end of the greenhouse and a pump circulating water through and over a porous pad (Figure 2) installed at the opposite end of the greenhouse..


If all vents and doors are closed when the fans operate, air is pulled through the wetted pads and water evaporates. As each gallon of water is evaporated, 8,100 BTUs of heat energy are absorbed from the air by the water during the change from liquid to vapour. Removing energy from the air lowers the temperature of the air being introduced into the greenhouse. The air will be at its lowest temperature immediately after passing through the pads. As the air moves across the house to the fans, the air picks up heat from solar radiation, plants, and soil, and the temperature of the air gradually increases. The resulting temperature increase as air moves down the greenhouse produces a temperature gradient across the length of the greenhouse, with the pad side being coolest and the fan side warmest.

FACTORS THAT INFLUENCE FAN AND PAD EVAPORATIVE COOLING SYSTEM
Operational considerations
It is very important to keep the building as tight as possible so entering air will be forced through the pads. Make sure that all doors and other openings are kept closed except when in use and that any gaps in the greenhouse coverings are sealed. If not, air will be pulled through these openings rather than through the cooling pad. The efficiency of a fan and pad cooling system depends on air moving through the cooling pads.

House Location and Orientation
Orientation of the greenhouse relative to other buildings or structures and in relation to prevailing summer winds influences the efficiency of operation. Fan arrangements and locations of the fans and pads should be determined by greenhouse location and orientation.

Type of Cooling Pad
The most widely used type of pad material is corrugated cellulose that has been impregnated with wetting agents and insoluble salts to help resist rot. When properly maintained these pads do an excellent job of cooling air. With proper maintenance, corrugated pads should have a lifetime of ten years.
Aspen pads were commonly used in the past. However, under hot conditions the life of an aspen pad is usually short. Aspen pads are very susceptible to algae infestation that leads to rotting and compaction. This makes it difficult to keep a system operating efficiently without frequent and costly pad replacements.
Other pad materials are also on the market, but none have seen wide acceptance. Among these are pads fabricated from aluminium and from plastic fibres. Both these pads types are expensive and show no advantages over corrugated cellulose. Comparing costs, life expectancy claims, cooling efficiencies, and probability of maintenance problems the one that is best is corrugated cellulose Pads.

Cooling Pad Area
The amount of pad area needed depends upon several factors including the type of pad material used. The pads should be continuous along the entire length of the wall. Cellulose pads can be used with airflows of up to 230 cubic feet per minute per square foot of pad. The higher airflow rates of cellulose pads, means that fewer square feet of pad area are needed than if aspen pads are used.

Water Flow Rate
To maximize operating efficiency, you must have adequate pad surface area and an adequate water supply and distribution system. Complete pad surface wetting occurs when about 1/3 gallon of water per foot of pad length is recirculated. A valve should be placed in the line from the pump so the water flow through the distribution pipe can be adjusted. You do not want a sheet of water flowing down the pad surface. This would increase resistance to air flow and cause transfer of free water into the house. You do want the pad surfaces covered with a water film. If in doubt about the correct quantity of water flow, check with the pad manufacturer. The water collected by the bottom gutter is returned to a sump from which the water is pumped to the upper distribution pipe or gutter. If water distribution pipes are more than 75 feet in length, the sump should be located near the center of the line. The sump should have a capacity of 1 to 1 1/4 gallons for each linear foot of pad in order to hold the water that drains back to the sump when the system stops.

Airflow Through Cooling Pads
The required face velocity of the air will depend upon the pad material. This velocity will determine the number of square feet of pad area needed for a house of a given configuration. Locate the pad so that all air entering the house will have to pass through the pad. Provide a method of closing off the pads during the winter when heating, not cooling, is required.

Fans
Regardless of the type of pad material used, the fans should have the capacity to provide a minimum of one air change per minute in the greenhouse. Equip the fans with automatic shutters to eliminate back drafts when a fan is not operating