Two-level hot and cold from KL
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• A new low-cost automatically controlled two-level forced-ventilation and heating system has been designed by KL Automotive Products Ltd. The system, which is claimed to give at least 60 air changes an hour, has been developed in co-operation with A. Moseley (Continental) Ltd, of Loughborough, which markets the Caetano range of bus and coach bodies made in Portugal.
The KL system has air ducts at both floor and ceiling level with inlets and outlets precisely positioned where the aerodynamics of the air flow around the vehicle give the pressure or suction required.
One three-position switch, operated by the driver, determines whether the vehicle is to be cooled or heated: the rest of the control is automatic being operated by a thermostat registering the inside temperature. The control temperature can be adjusted, and that selected is indicated on a dial.
The automatic heaters have electrically operated flaps which close or open the air intakes and thus maintain the chosen temperature. When the temperature is at or above the desired level the air valves are open drawing in fresh air and when t temperature is below this level the air recirculated by the heater fans. The enti installation, while maintaining complete ye tilation, has the heating capacity equivale to 32 I000-watt electric fires. Air circulatio is automatically provided through the hea ers when the coach is in motion by t extraction outlets in the roof of the vehicl and this can be augmented by extractor fa which are also used when the vehicle stationary. Two outer fans and ducts pr vide cool air circulation at head level a this is also helped by four more fans, in row, in a ventilation box at the rear dome the vehicle and which are also operated the driver's switch.
Tests in Portugal by KL enginee showed that with an ambient temperature 92deg F the temperature inside a Bedfo YRQ with Caetano body rose to 128deg in half-an-hour. Within 10 minute however, of the cooling system bein switched on the inside temperature had bee reduced to within 5deg of the outside ten perature.
The whole system, says KL, weigt I70lb and is a fraction of the cost of refrigerated air-conditioning system.