Warsash
| Summary Polycast Ltd, a foundry in Southampton, recently installed a heat pump to replace a gas-fired heater for mould drying. The heat pump air drier/heater supplies air with a controlled supply air temperature of 25șC. It is located in the existing high air velocity drying chamber. The products being dried require to be kept at a very constant temperature. The heat pump drier closely controls the amount of refrigerant reheat to the cooled dry air in order to meet the requirement of ± 0.75șC supply air temperature. The COP ranges from 3 to 5.8 depending on the amount of reheat used. A significant reduction in failed ceramic casing in mould has yielded a considerable reduction in the operating costs.
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Since the installation of the heat pump the drying time for ceramic coating on wax moulds has been reduced. The control of supply air temperature and dryness of the air have reduced high mould wastage to none. Wastage mould originates from cracking of ceramic coating such that damaged product cannot be used. |
Industry/process
| Industry type: | Foundry | |||
| Location: | Warsash, Southampton, UK | |||
| Description of the process: | - | |||
Heating pump system
| Application: | Mould drying | |||
| Heat pump type(s): | Closed cycle compression | |||
| Heat pump installed capacity (kW) | 34 (8.5 run round coil and 25.5 cooling) | |||
| Drive energy: | Total input: 6.4 kW compressor, 0.5 kW fan | |||
| Refrigerant: | R417a | |||
| Heat pump system completion date: | July 2001 | |||
| Description of the heat flows: Air is cooled to 2șC saturated and reheated to 21șC saturated. Surplus heat is rejected to atmosphere. |
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Performance
| Energy | |
| Heat pump drive energy (kWh/year): | 28 000 |
| Fuel: | Electricity |
| Energy output, useful heating (kWh/year): | 290 496 if 24 h a day |
| Energy output, useful cooling (kWh/year): | No data |
| Energy cost (GBP/kWh): | 0.052 |
| Coefficient of performance (COP): | 3 to 5.8 depending on the amount of reheat used |
| Test conditions: | No data |
| Heat pump cost breakdown | |
| Heat pump only (GBP): | 14 898 |
| Installation (GBP): | 358 |
| Capital cost (excluding heat pump) (GBP): | 1 525 (Ducting & grilles) |
| Maintenance: | No data |
| Alternative system (if has been considered) | No data |
| Payback | Unknown. As much as a third of the product was lost (cracked ceramic) when the previous system, a gas-fired heater, was used. With the heat pump system a reduction in failed ceramic casing in mould has yielded a considerable reduction in operating costs. |
| CO2 emissions | No data |
Operational experience and other comments
A roof-mounted unit connected to ducting was installed. Installation and commissioning took a total of 3 man days.
In the present climate out of 24 h use the compressors have been monitored as being in operation for 16 h out of the 24 h.
Operation conditions of 40-45% humidity and temperature 22-23șC have been maintained.
Maintenance is excellent and only weekly cleaning of washable return air filters is required.
According to the mould company the reliability is excellent.
Contacts
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Contact 1: |
Susan Ricketts |
| Company: | Braeaire Ltd |
| Role: | Equipment design and manufacturer |
| Address: | Unit 18, Belgrave Industrial Estate Portswood, Southampton SO17 3EA UNITED KINGDOM |
| Telephone: | + 44 23 8055 6866 |
| Fax: | + 44 23 8032 2581 |
| Email: | anex @ btinternet.com |
| Last updated: 1 March 2004 |
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