Some concepts just make sense- like when the developer of a solar powered pontoon boat pointed out-"Since most recreational boating is done when the weather is nice, solar power is particularly well adapted to the task." The same holds true for a solar powered air conditioner- when do you need it? When it is hot and sunny.
 
Absorption chillers use thermal energy sources to produce chilled water. Water has a very high specific heat and latent heat of vaporization, which makes it a great refrigerant. How is water boiling at 212°F going to create chilled water at 44°? First, the boiling temperature of water is a direct function of pressure and at a pressure of 1 atmosphere (29.92 Hg), water boils at 212°. When the pressure on the water is decreased, the water boiling temperature is lowered. Absorption chillers have substantially reduced internal pressures to take advantage of the lower water boiling temperatures. Absorption chiller internal pressures can range from 0.1 atmosphere (atm) to below 0.01 atm.
There are a number of absorption chillers available, including single-effect indirect-fired (steam, hot water); double-effect indirect-fired; and double-effect direct-fired (gas and/or oil burner). Single-effect absorption chillers have a single generator/concentrator and condense all vaporized refrigerant in a single condenser. Double-effect absorption chillers have two generator/concentrators and the vaporized refrigerant from the high temperature generator/concentrator is the thermal source for the low temperature generator/concentrator, reducing the cooling requirement for the vaporized refrigerant (See Figure 2).

The single-effect indirect-fired absorption chiller has five main steps (Figure 1): 1) condensing (condenser), 2) expansion (expansion pipe), 3) evaporation (evaporator), 4) absorption (absorber), and 5) generator/concentrator.


1) Condenser. In the condenser, the cooling water absorbs the heat of condensation from the vaporized refrigerant, changing the refrigerant into a liquid.

2) Expansion. The liquid refrigerant (water) travels from the condenser through expansion piping to the evaporator during which the liquid refrigerant experiences a drop in pressure and temperature.

3) Evaporator. The liquid refrigerant (water) is pumped to the chilled water tube bundle top and sprayed on the tube bundle. At the low evaporator pressure, the liquid refrigerant vaporizes at approximately 38°, removing energy from the chilled water. Liquid refrigerant that is vaporized travels from the evaporator to the absorber.

4) Absorber. The vaporized refrigerant enters a liquid lithium-bromide solution spray within the absorber. The lithium bromide solution absorbs the vaporized refrigerant and the cooling water absorbs the heat of vapor absorption. After the absorption, the liquid lithium-bromide solution takes one of two paths. One path has the liquid bromide solution mixing with a concentrated lithium bromide solution and being pumped to the absorber spray nozzles. The other path has the liquid bromide solution being heated and pumped to the generator/concentrator.

5) Generator/concentrator. The lithium-bromide solution enters the generator/concentrator and is heated by steam or hot water, raising the lithium bromide solution to a temperature where the liquid refrigerant (water) vaporizes and travels to the condenser, completing the refrigerant cycle. The concentrated lithium bromide solution flows down to the absorber, completing the absorber cycle.

Types of Refrigeration Systems

• Vapour Compression Refrigeration (VCR): uses mechanical energy

• Vapour Absorption Refrigeration (VAR): uses thermal energy

Advantages of Absorption Refrigeration System

• The capital cost and running cost are less per unit of refrigeration.

• Absorption unit can be built in capacities well above 1000 tons each which is the largest size for single compressor unit.

• It can be located away from the air conditioned places which is useful and less costly.

• Steam which is bled from the turbine is used for winter heating ,the same steam can be used for refrigeration in summer supplying to the

generator.

• Noise and vibration troubles are less to the people living in air conditioned places as the air conditioned pant is far away from air

conditioned places.

• Better accessibility for maintenance. No compressor hence 100% saving on electricity bills towards largest power consuming component i.e. compressor.

• No moving parts, Silent, No compressor, hence No costly maintenance.

• The absorption refrigeration unit can operate at reduced evaporator temperature by increasing the steam pressure which is supplied to the generator with little decrease in capacity.

• Analyzer and rectifier are not required in this system as LiBr (absorbent) is not volatile.

Solar Assisted Air Conditioning System

• The outside hot wet air is passed through the dehumidifier.

• Where a spray of desiccant (tri-ethylene glycol which absorbs moisture from air) is done

• The desiccant becomes weak as it absorbs water vapour from the air.

• The heat of condensation is removed by a water coil. the water from the cooling tower is circulated through the water coil with the help of pump, the dry cooling air coming out of dehumidifier is supplied to the air-conditioned system.

• The basic Solar system used in this arrangement consists of collector and a storage tank

• The fluid which collects the solar heat from the collector is circulated through a closed loop as shown in figure. This helps to collect solar heat even the ambient temperature falls below zero deg C. ( if water is used as fluid, it may freeze in the collector when the temperature of the ambient air falls sub zero

temperature).

• The heat from the storage tank is then used in concentrator as explained earlier. The heat in the storage tank is also used to provide domestic hot water through a heat exchanger.

• The major advantage of this system is , it uses low temperature Solar heat for the purpose and some pre-cooling of air is accomplished during the dehumidification process it self.

Space Required

• 1 ton refrigeration = 3024 Kcal/hr heat rejected

• One dish gives 3000Kcal/hr from one dish. Of 16.5 m2 area

• Therefore approximately for one ton of refrigeration we require

one dish of 16.5m2.

• Each dish requires Approximately 35 m2 area with (receiver) on

floor space.

Applications

• Ice Manufacturers

• Food Preservation

Commercial Applications

• Air conditioning of Hotels and restaurants
• Air conditioning of Departmental Stores
• Air conditioning of Theatres and Auditorium
• Air conditioning of hospitals
• Air conditioning of offices
• Air conditioning of cinema halls, malls

Industrial Applications

• Ice cream manufacturers
• Refrigeration of Breweries

Features of SGN’s Solar Air conditioner:

• No moving parts, Silent, No compressor, hence
• No costly maintenance.
• No CFC, 100% Eco Friendly design an Effective step to protect Ozone depletion.
• Novel concept using Solar Thermal Energy for Air Conditioners
• Operates above 93%COP.
• Sub zero temperature possible.
• Wide range of capacities varies from 10TR. to 600 TR even above.
• Large parabolic Solar Concentrator offers most efficient output.
• Centrally controlled automatic Sun Tracking mechanism.
• Extended period of operations possible even after Sunny hours.
• Do not require highly qualified personnel to maintain the system.
• Attractive and Elegent FCU’s.
• True RH control for most comfortable environment.

Benefits  of SGN Solar Air Conditioner:

• No compressor hence 100% saving on Electricity bills towards largest power consuming

component i.e. Compressor

• Free hot water approx. 10,000 Ltrs. Per Day@ 55 C from 10TRsystem.
• No need to have additional system for Hot Water Generation. which results in saving on capital investment as well as on running cost.
• Free cool drinking water approx 1,500 Ltrs. Per Day@18 C from 10TRsystem.
• Pay back period works out to be less than two years.
• 80% depreciation in 1st year itself under section 32 of income tax Act 1956.
• Subsidy to the tune of 50% from MNES on Solar System.
• User can be eligible for getting World recognized Eco-friendly awards
• Can easily be configured to existing system with quick change over mode.