Water in the relatively low temperature range of 70 °C ~ 95 °C may be used in the absorption cycle to produce chilled water for comfort cooling purposes.
The WFC machine is particularly useful where heat recovery systems are proposed. For example, cogeneration, district heating systems, industrial waste heat, geothermal springs, thermal solar systems, or biomass installations - in fact anywhere low cost energy can be produced.
Yazaki WFC-series produces 7 °C chilled water, precisely the same as the gas fired CH chiller-heater.
As a result, they are perfectly compatible for a concept of parallel installation.
Yazaki units may be switched on and off using manual or automatic controls and may be easily started up from a distance using remote control and regulation units. Liberal use of advanced technology ensures extremely economical operation and great reliability. A step control makes it possible to keep the multiple-unit Yazaki units’ performance high, stabilising operation according to the required load. A modular microprocessor constantly monitors the load factor and automatically selects the optimum number of units in operation.
Yazaki units are fitted with fully waterproof cladding panels whose surfaces are treated to withstand even the most aggressive atmospheric forces.
The units normally use cooling towers to reject heat.
The basic models in the range cover ratings ranging from 35 to 105 refrigerating kW, are of modular design, and are inter-compatible, thus making it possible to design systems with multiples of the basic ratings.
Yazaki units are certified in accordance with the EU directives.
Drastic Cut in Fuel Costs
The fact that the appliances run on the thermal energy contained in recycled hot water obviously makes for a drastic cut in fuel costs. The Yazaki units, which run on waste heat of any origin, may be classed as full-fledged energy recyclers and thus benefit from the incentives provided under the laws currently in force.
Very Low Electricity Consumption
The primary energy used is thermal. Electricity is used only to run the auxiliary control, fluid circulation, and heat exhaust appliances. No electricity transformation cabin is thus required.
Yazaki appliances are designed for outdoor installation, even at locations, such as coastal and industrial sites, where the atmosphere is particularly aggressive. Utility rooms to house the refrigeration plant are no longer required. Where appliances are installed indoors, the units’ compactness means that they take up very little space.
Modest Plant Cost
Yazaki units are extremely compact. Their modular design facilitates haulage and installation operations. All the units are precharged with lithium bromide solution and tested at the factory. Start-up operations are thus very simple and rapid and prevent any of the solution from being given off into the environment. The system is thus simple and compact, and is in many cases less costly that the traditional, compression-unit model.
The high reliability for which absorption units of the Yazaki type are widely renowned is due to their limited number of moving mechanical parts. The very simplicity of design of such appliances is in itself a guarantee of reliability, as is certified by the ASHRAE (American Society of Heating,Refrigeration, and Air-Conditioning Engineers).
Being fully sound-proofed, Yazaki units are extremely quiet and vibration-free. They are ideal for installation in conurbations as well, on solar flooring, on terraces, in attics, in gardens and in the courtyards of premises built for trading, industrial, and service businesses.
The small number of moving mechanical parts cuts down the number of components subject to wear and tear, and therefore requiring inspection and replacement.
Low Environmental Impact
Yazaki units do not uses CFC’s or HCFC’s, which are extremely damaging to the environment and have now been banned. What is more, the primary energy used reduces emissions of harmful products of combustion.
The water fed in heats the dilute lithium bromide and water solution contained in the generator to boiling point. Boiling releases water vapor (refrigerant) and strengthens the lithium bromide solution. The concentrated solution is collected and pre-cooled, by being passed through a heat exchanger, prior to being fed into the absorber.
The refrigerant vapor reaches the condenser, where it condenses on the surfaces of the chilling circuit coils. The condensation heat is removed by the cooling water and exhausted through the evaporation tower. The refrigerant liquid collected in the condenser is then fed into the evaporator through the opening provided for the purpose.
The influence exerted by the absorber makes the pressure inside the evaporator substantially lower than the generator and condenser pressure. Once inside the evaporator, the refrigerant liquid thus boils and absorbs heat, evaporating on the surface of the coil in the circuit containing the water to be chilled. The refrigerant vapor thus obtained thus flows into the absorber.
The low pressure in the absorber is due to the chemical affinity between the concentrated lithium bromide solution supplied by the generator and the refrigeration vapor that forms in the evaporator. The refrigerant vapor is absorbed by the concentrated lithium bromide solution as the latter bathes the surface of the absorber coil. The condensation and dilution heat is drawn off by the cooling water. The dilute lithium bromide solution is then preheated in the heat exchanger prior to being returned to the generator.