Industrial news No uvelles de I'in dustrie

Heat pump bureau

A heat pump and air conditioning bureau has been launched by the Electricity Council. It aims to advise and provide information for both users and suppliers of heat pumps and air conditioning units.

Heat pumps have rapidly grown in popularity as energy prices have risen. Concern has been expressed by both HVCA (Heating and Ventilating Contractors Association) and the Electricity Council that heat pumps should be designed, installed and maintained to high standards.

In association with this, a draft standard document to cover safety and performance testing of heat pumps in the UK has been prepared.

The Heat Pump and Air Conditioning Bureau, 30 Millbank, London SW1P 4RD, UK

Glycol defrost

A glycol deforst system for commercial refrigerated display cabinets has been installed in the UK. The absence of electrical defrosting has reduced the power requirements and removed the need for three-phase electrical supplies to the display cabinets. Glycol pipes are run through the finned evaporators rather than the usual electrical coil heaters.

A heat exchanger is interposed between compressors and the condenser, transferring heat to two circuits - one for defrosting and one for space heating. Glycol in the defrost circuit is pumped through an insulated tank, so the temperature of the glycol

increases. To defrost the cabinet, the glycol is circulated through the finned evaporators in the cabinet. During defrost the cabinet temperature stays almost constant, so there is no partial defrosting of the top layer of products. The defrost is thermostatically ended when the evaporator coils are free of ice but, as a safety back-up, a time- switch will switch off the defrost system.

The other secondary circuit in the heat exchanger contains water, which when heated, serves to heat the sales and storage areas.

Fastfreeze Limited, 506 Holderness Road, Hull, North Humberside HU9 3DS, UK

Temperature gauge

A differential temperature gauge covering the ranges 0°C to ±100°C and 0°C to ±10°C is available. Startronic say this Model 1 65 can detect changes of ±0.2°C. The input is from thermistors which can be unshrouded, or gas or liquid probes, or surface mounting sensors. When probes are changed, recalibration is unnecessary. Very long leads for the sensors can be used, allowing differential temperature measurement at points which are metres apart.

No external power source is required. There is also a preset control which allows measurement of small temperature changes about any point between 0°C and + 100°C. This control is used in the non-differential mode.

Startronic Limited, Beeching Road, Bexhill-on-Sea, Sussex TN39 3LG, UK

Model 165 portable differential temperature gauge from Startronic

Altitude/temperature chamber

Altitude/temperature chambers have been designed for testing materials in simulated altitude environments up to 200000 ft (60 960 m) and at temperatures from -73°C to +177°C. Each unit of the ZFA-2100 series has an integrated heater and refrigeration system to control temperature.

Optional extras include a humidity control for 20--95% humidity; cam-type automatic programmers for temperature or altitude, and a microprocessor programmer for temperature and/or humidity and altitude; and recorders for the three functions.

Associated Environmental Systems, 360 Merrimack Street, Lawrence, MA 01842, USA

Modular floor heating

Frost heave in cold stores can be prevented by using heating equipment. A modular construction under-floor heating has been developed by Loheat, so if the cold store is dismantled and resited, the same heating system can be relaid.

The individual modules are manufactured using ~ in (1.9 cm), 8ft by 4ft (2.44 m by 1.22 m) insulation panels, with stainless

Volume 4 Number 5 September 1981 301