Objective
Recovery of heat from hudraulic oil, air compressor and mould chilling circuit in form suitable for space and some process heating. Reduction of hydraulic power consumption by 30 % and energy for mould chilling by 80 %. The new designed system :
A) Reduce the chilling load by the use of a novel mould temperature controller.
B) Substancially reduce the hydraulic power required to operate the moulding machine by using a centralised hydraulic power pack.
C) Will have a centralised energy conservation and heat recovery system. Innovation lies in the novelty of the proposed system. Expected energy saving 1,696,129 kWh/year. Pay-back 1.2 years.
Recovery of heat from hydraulic oil and compressor has been completely successful. Recovery of heat from the mould chilling circuit has proved impractical owing to failure of chiller to achieve guaranteed performance when using cooling water at 36 deg. C. An existing air cooled condensor is being modified to provide warm air at 40 deg. C. to space heat an adjacent Warehouse.
The mould heating circuit has been completely successful as has the original mould temperature controller. Modifications to the temperature controller are planned, using variations in temperature of the heat transfer media to control transfer rate. It is hoped to improve control and reduce cooling time, such that "ideal" mould interface temperature vs time curves can be reproduced automatically.
Preliminary monitoring of hydraulic power usage showed that over 50 % of hydraulic power is lost during plasticisation and solidification, when practically no mechanical work is being done. Design of centralised hydraulic power circuit is being modified to reduce this primary power loss.
Modulating control valves on compressor oil cooling circuit (to divert hot oil from heat recovery to air cooling) have proved unsatisfactory and have been replaced by on-off control.
About 300 injection moulding plants in the UK are considered large enough to benefit from the systems. All plants (2,000) are expected to benefit from improved mould temperature control. Potential for replication in the European Community is estimated at six times this number.
Licenses are available throughout Europe (but excluding the UK) under European Patent Application No. 88301997.8 and UK Application No GB 8822086.8 ("Improved microprocessor based mould temperature controller"). European Patent Application covers "Heat recovery from Hydraulic Oil".
Joint ventures with one or more major European moulding machine manufacturers are sought with a view to modifying the design of their machines to incorporate our hydraulic oil cooling and mould temperature control circuits.
Heat is being recovered from the hydraulic oil for space heating; and from the oil cooled compressor for space heating, for pre heating moulds after shut-downs and maintaining mould temperature during temporary shut-downs.
A novel microprocessor based mould temperature controller is being used in conjunction with hot water from the hydraulic oil cooling circuit at 36 deg.C. and 46 deg.C. and with normal chilled water at 12 deg.C. to reduce the mould heating and chilling costs. As a result of work carried out so far it is now planned to modify the controller to obtain reproducable mould interface temperature vs time curves by controlling temperature difference between heat transfer medium and mould interface (See separate report).
The technology is operating in medium sized plastics injection moulding shops employing between 150 and 300 persons on a 3 shift basis.
Topic(s)
Call for proposal
Data not availableFunding Scheme
DEM - Demonstration contractsCoordinator
BH4 2DR Bournemouth
United Kingdom