Trondheim
Research Centre
Norway - Seawater-source heat pump
Summary
A large capacity ammonia heat pump was installed in 1994 at the STATOIL Research Centre in Trondheim. The building is a work site for about 500 people. The heat pump uses seawater as a heat source and has a COP of 4.0 at design conditions. The annual energy savings compared to a conventional oil-fired heating system and a conventional air-conditioning system are significant: 2.3 GWh of thermal energy for heating and 0.4 GWh of electricity for cooling. Due to the toxicity of ammonia a number of safety measures have been taken to meet the safety standards.
Building and design values
| Building type: | Research centre | |||
| Location: | Trondheim, Norway | |||
| Year of construction: | No data | |||
| Number of storeys: | No data | |||
| Heated floor area (m2): | 28 000 | |||
| % of total floor area (%): | No data | |||
| Design outdoor temperature (ºC) | Heating: | No data | Cooling: | No data |
| Design indoor temperature (ºC) | Heating: | No data | Cooling: | No data |
| Degree days | Heating: | No data | Cooling: | No data |
| Base temperature for degree days (ºC) | Heating: | No data | Cooling: | No data |
Heating and cooling
| Application: | Space heating and cooling | |||
| Heat pump type(s): | Water-to-water | |||
| Heat pump installed capacity (kW) | Heating: | 2 x 450 | Cooling: | No data |
| Refrigerant: | Ammonia | |||
| Heat source | Seawater (5-6ºC) | |||
| Details: | The condensers are installed in parallel and the evaporators in series. The capacity of the heat pump and the heat supply temperature are proportional to the outdoor temperature. | |||
| Distribution system(s): | No data | |||
| Supply and return temperature (ºC) | Heating: | - | Cooling: | 5-6/- |
| Auxiliary system: | Boilers | |||
| a) Size (kW): | 2 x 1 400 | |||
| b) Fuel: | Propane | |||
| c) Operating regime: | Peak loads and back-up | |||
| Heat pump design: | Designed to cover base load, covering about 40% of the maximum heating capacity at design heating conditions | |||
| Supplementary system: | Ammonia chiller (200 kW) as back-up for cooling | |||
| Heat pump system completion date: | 1994 | |||
Performance
| Heating energy | Heat pump | Aux. heating system1 | Auxiliaries |
| Energy input (kWh/year): | 1 300 000 | 900 000 | - |
| Energy output (kWh/year)2: | 3 900 000 | 800 000 | n/a |
| Cooling energy | No data |
| DHW | No data |
| Additional notes | Optimisation of temperatures and circulating water volumes will contribute to increase the thermal energy from the heat pumps and the energy savings. Compared to a conventional oil-fired heating system and a conventional air-conditioning system, the annual energy savings are verified to a minimum 2.3 GWh of thermal energy and 0.4 GWh of electricity for cooling. |
| Coefficient of performance (COP) | |
| Heating: | 4.0 |
| Test conditions: | Design conditions |
| Cooling: | No data |
| Test conditions: | No data |
| Heat pump cost breakdown | |
| Heat pump only (NOK): | 3 600 000 |
| Installation (NOK): | |
| Capital cost (excluding heat pump) (NOK): | |
| Maintenance (NOK): | No data |
| Alternative system (if has been considered) | No data |
| Fuel cost | No data |
| Payback | The payback is 4.5 years. The profit of cooling by seawater is not included in the calculation. |
| CO2 emissions |
Compared to a conventional oil-fired system the reductions of emissions are estimated
as:
|
Operational experience and other comments
The machine room is located inside the office building. Because of this leak detectors are connected to an alarm system and to the fail-safe mechanical ventilation system with two-speed fans. The heat pumps have low charge ammonia units and sectioning of the refrigerant circuits. In order to avoid a possible leakage of ammonia vapour to the offices or the surroundings of the building, an ammonia scrubber has been installed to reduce the ammonia concentration in the exhaust air to an acceptable level, below 50 ppm. The total ammonia charge is as low as 180 kg.
References
This case study is presented on the Caddet website at
http://www.caddet.org.
| Last updated: 1 March 2004 |
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