Phone now today before 3pm for immediate dispatch.

Tel: 01536 525136
Fax: 01536 481569

alex@rackett.freeserve.co.uk

Air Conditioner Shack,
Unit 2, Torridge Close,
Telford Way Industrial Estate,
Kettering,
Northants.
NN16 8PY

London office:
Unit 52 Newark Crescet, Park Royal Ind Est, London, NW10 7BA.
Tel: 01536 484 733

There are many types of air conditioning systems available and therefore there are factors to take into consideration when choosing a suitable system:

Capital Cost: Includes not only the cost of equipment and its installation, but also all ancillary requirements such as build work, plant location and size, electrical work, progress time, administration, etc. Whole life costs also consist of maintenance, energy efficiency and life expectancy.

Energy Efficiency (Running Cost): Energy efficiency of air conditioning systems is becoming increasingly important as it can account for the largest single element of the energy requirement of a building. Also, in the near future, energy tax might be introduced. It may be more cost effective to install a system with higher initial cost but which provides greater energy efficiency.

Maintenance Cost: Maintenance cost is often over looked in any calculation and can be very costly dependent on the complexity of the system and the availability of professional service companies.

Flexibility: Flexibility of the system should be assessed in terms of installation, operation, future expansion and changes, operation, maintenance and controls.

User friendliness: This needs to be assessed in relation to the occupier or user, the operator and/or the maintenance personnel. Many systems have standard controls, which are simple in concept yet sophisticated in nature and can combine user friendliness with full technical diagnostics.

Environmental Issues: These need to be checked, such as equipment compliance with current and future legislation in terms of CO₂ emissions, Ozone Depletion & Health & Safety.

Common terms :

ABSOLUTE ZERO: Absolute zero is that temperature at which molecular motion stops. It is the lowest temperature possible. There is no more heat in the substance at this point.

AIR CONDITIONER: Device used to control temperature, humidity, cleanliness, and movement of air in conditioned space.

BOILING TEMPERATURE: Temperature at which a fluid changes from a liquid to a gas/vapour. At atmospheric pressure water boils at 100°C, refrigerant (R22) at -40.8° C.

BRINE: Water saturated with chemical such as salt.

CAPACITOR: Type of electrical storage device used in starting and/or running circuits on many electric motors.

CARBON FILTER: Air filter using activated carbon as air cleansing agent.

CHLOROFLUOROCARBON (CFC): A compound containing chlorine, with high risk of damaging the ozone layer.

COEFFICIENT OF PERFORMANCE (COP): The ratio of work or energy applied as compared to the energy used.

COMPRESSOR: The pump of a refrigerating mechanism which draws a vacuum or low pressure on cooling side of refrigerant cycle and squeezes or compresses the gas into the high pressure or condensing side of the cycle.

COMPRESSOR, HERMETIC: Compressor in which driving motor is sealed in the same dome or housing that contains the compressor.

COMPRESSOR, OPEN-TYPE: Compressor in which the crankshaft extends through the crankcase and is driven by an outside motor.

COMPRESSOR, RECIPROCATING Compressor, which uses a piston and cylinder mechanism to provide pumping action.

COMPRESSOR, ROTARY: A compressor, which uses vanes, eccentric mechanisms, or other, rotating devices to provide pumping action.

COMPRESSOR, SCROLL: A compressor which uses two scrolls, one is fixed while the other revolves in orbit to provide pumping action.

COMPRESSOR, SCREW: A compressor which consist of rotors having male and female gears and compresses by engaging one screw rotor and two gate rotors to provide pumping action. COMPRESSOR, CENTRIFUGAL: A compressor, which consists of impeller and volute. The impeller rotates at aprox. 10,000 rpm. Such force changes the gaseous refrigerant into speed energy, which is converted into pressure energy for compression.

CONDENSING TEMPERATURE: Temperature at which a gas changes from a gas to a liquid.

CONDENSER: The part of refrigeration mechanism which receives hot, high pressure refrigerant gas from compressor and cools gaseous refrigerant until it returns to liquid state.

CONDENSING UNIT: That part of refrigerating mechanism which pumps vaporised refrigerant from evaporator, compresses it, liquefies it in the condenser and returns the liquid refrigerant to refrigerant control.

COOLING TOWER: Device, which cools water by water evaporation in air. Water is cooled to wet bulb temperature of air.

CRYOGENICS: Refrigeration which deals with producing temperatures of 250°F below zero (- 157°C) and lower.

D-BACS (Daikin Building Air Conditioning Control System): Computer operated control/management system utilising information generated by Daikin and other equipment.

DEFROST CYCLE: Refrigerating cycle in which evaporator frost and ice accumulation is melted. 

DEHUMIDIFIER: Device used to remove moisture from air in enclosed space.

DRY BULB: An instrument with sensitive element, which measures ambient (moving) air temperature.

DRY BULB TEMPERATURE: Air temperature as indicated by ordinary thermometer.

ELECTROSTATIC FILTER: Type of filter, which gives particles of dust electric charge. This causes particles to be attracted to a plate so they can be removed from air stream or atmosphere.

ENERGY: Energy is the capacity or ability to do work.

EVAPORATION: A term applied to the changing of a liquid to a gas. Heat is absorbed in this process.

EVAPORATOR: Part of a refrigerating mechanism in which the refrigerant vaporises and absorbs heat.

EXPANSION VALVE: A device in refrigerating system which maintains a pressure difference between the high side and low side and is operated by pressure.

FREEZING POINT: The temperatures at which a liquid will solidify upon removal of heat. The freezing temperature for water is 32°F (0°C). at atmospheric pressure. 

GRAIN: A unit of weight and equal to one 7000th of a pound (0.064 grams). It is used to indicate the amount of moisture in the air.

HEAT RECLAIM VENTILATION (HRV): Ventilation system operates on the principle of reclaiming energy from exhaust air.

HEAT: Heat is a form of energy. It is related to the molecular motion or vibration. HEAT EXCHANGER: Device used to transfer heat from a warm or hot surface to a cold or cooler surface. Evaporators and condensers are heat exchangers.

 HEAT LOAD: Amount of heat, measured in Btu, which is removed during a period of 24 hours.

HEAT PUMP: A compression cycle system used to supply heat to a temperature controlled space, which can also remove heat from the same space.

HEAT TRANSFER: Movement of heat from one body or substance to another. Heat may be transferred by radiation, conduction, convection or a combination of these three methods.

HORSEPOWER: A unit of power equal to 33,000 foot pounds of work per minute. One electrical horsepower equals 746 watts.

HUMIDIFIERS: Device used to add to and control the humidity in a confined space.

HYDROCHLOROFLUOROCARBON (HCFC): A compound containing chlorine but since hydrogen is present, the risk of damaging the ozone layer is low.

HYDROFLUOROCARBON (HFC): A compound which does not contain chlorine and does not damage the ozone layer.

HUMIDITY: Moisture; dampness. Relative humidity is ratio of quantity of vapour present in air to greatest amount possible at given temperature.

LATENT HEAT: Heat energy absorbed in process of changing form of substance (melting, vaporisation, fusion) without change in temperature or pressure.

POWER: Power is the time rate of doing work.

PSYCHROMETER OR WET BULB HYGROMETER: An instrument for measuring the relative humidity of atmospheric air.

PSYCHROMETRIC CHART: A chart that shows the relationship between the temperature, pressure and moisture content of the air.

REFRIGERANT: Substance used in refrigerating mechanism to absorb heat in evaporator coil by change of state from a liquid to a gas, and to release its heat in a condenser as the substance returns from the gaseous state back to a liquid state. 

RELATIVE HUMIDITY: Ratio of amount of water vapour present in air to greatest amount possible at same temperature.

REVERSING VALVE: Device used to reverse direction of the refrigerant flow depending upon whether heating or cooling is desired.

SENSIBLE HEAT: Heat, which causes a change in temperature of a substance.

SHELL_AND_TUBE FLOODED EVAPORATOR: Device, which flows water through tubes, built into cylindrical evaporator or vice-versa.

SHELL TYPE CONDENSER: Cylinder or receiver, which contains condensing, waters coils or tubes.

SKYAIR: Skyair is a trade name of Daikin middle range split systems. SOLAR HEAT: Heat from visible and invisible energy waves from the sun.

SPECIFIC GRAVITY: Weight of a liquid compared to water, which is assigned value of 1.0.

SPECIFIC HEAT: Ratio of quantity of heat required to raise temperature of a body one-degree to that required to raise temperature of equal mass of water one degree.

SPECIFIC VOLUME: Volume per unit mass of a substance. 

SPLIT SYSTEM: Refrigeration or air conditioning installation, which places condensing unit outside or remote from evaporator. Also applicable to heat pump installations.

SUBCOOLING: Cooling of liquid refrigerant below its condensing temperature. SUCTION LINE: Tube or pipe use to carry refrigerant gas from evaporator to compressor.

SUPERHEAT: Temperature of vapour above boiling temperature of its liquid at that pressure.

TEMPERATURE: Degree of hotness or coldness as measured by a thermometer; measurement of speed of motion of molecules.

THERM: Quantity of heat equivalent to 100,000Btu (105,500 kJ).

THERMOSTAT: Device responsive to ambient temperature conditions.

VACUUM PUMP: Special high efficiency compressor used for creating high vacuums for testing or drying purposes. VAV (Variable Air Volume): A central air conditioning system which works on the principle of supplying constant temperature air volume to a space, and by varying the volume, controls room temperature. 

VRF (Variable Refrigerant Flow): A direct expansion, modular central air conditioning system providing heating and cooling. Operates on the principle of varying the flow of refrigerant to a room terminal unit to achieve desired temperature.

VRV (Variable Refrigerant Volume): Trade mark for Daikin VRF systems:

VVT (Variable Volume Variable Temperature): Same principle as VAV, except two ducts are required, one for heating, one for cooling, with variable control dampers.

VWT (Variable Water Temperature): Same as VWV but changing both the volume and the temperature of the water to achieve room  temperature.

VWV (Variable Water Volume): A central water based system operating on the principle of supplying constant temperature of chilled/hot water to room terminals and varying the flow to achieve room temperature.

WET BULB: Device used in measurement of relative humidity. Evaporation of moisture lowers temperature of wet bulb compared to dry bulb temperature in same area.

WORK: Work is force multiplied by the distance through which it travels.

Refrigeration and Air Conditioning Kettering was founded in 1970's and has now become one of the most respected names in the UK air conditioning industry, distributing air conditioner products.

Philosophy : To sell the best and widest range of available products. To offer the best engineering solutions.To provide a complete service from training to delivery, seminars to design assistance and a complete range of complementary accessories. RACe's long term strategy has always been to develop the UK market from a position of strength via technical knowledge, experience and sound financial management supported by technical expertise and long term vision. RAC has high service standards and is committed to customer satisfaction, ensuring the customer receives the right system to suit their requirements and budget, perfectly, right from the very beginning.

Air conditioning in a motor vehicle is a combination of the car heater and a refrigerant circuit. This allows the desired climatic conditions to be maintained regardless of the outdoor conditions. This makes air conditioning a significant factor for safety and driving comfort. The refrigerant circuit. The individual components in the refrigerant circuit are connected with one another by hoses forming a closed system. The refrigerant circulates in the system driven by the compressor. The circuit is divided up into two sections: The section between the compressor and expansion valve is called the high-pressure side (yellow/red). Between the expansion valve and compressor we speak of the low-pressure side (blue). In the compressor the gaseous refrigerant is compressed and thereby heated highly. Under high pressure it is pressed through the condenser. Here heat is removed from the highly heated refrigerant causing to condense and thereby changing its state from gaseous to liquid. The drier, the next station, separates impurities and air inclusions from the now liquid refrigerant. This ensures the effectivity of the system and protects the components from damage resulting from contamination. Then it passes from the drier to the expansion valve. This valve is similar to a dam. In front of the dam it maintains a uniform pressure, and in back of the dam this pressure is relieved due to the increase in volume. Since the expansion valve is located directly in front of the evaporator, the refrigerant expands into the evaporator. During evaporation, a change in the state from liquid to gaseous, heat is absorbed from the surroundings. The evaporator is a heat exchanger similar to the condenser. It has an enormously large surface, over which it can absorb heat from the surroundings for evaporation. This cold air is then blown into the vehicle passenger compartment by the ventilation system where it ensures the comfort of the passengers. On the low pressure side the refrigerant is again gaseous flows to the compressor where the circuit starts over again.

Information on air conditioner :