Nibbixwoud
Summary
This is a new 5-storey building of a company, which supplies hand and nail-care products in the Netherlands. The building has dedicated areas for office work, light industrial handwork and storage.The system consists of a small heat pump, a high-efficiency boiler for peak loads and energy piles as the heat source. The ground is regenerated during the summer by free cooling. The seasonal performance factor (SPF) for heating is 5.15. The CO2 emissions are 39% lower than those of a conventional HVAC system with natural gas and electricity. |
Building and design values
| Building type: | Offices, light industrial handwork and storage rooms | |||
| Location: | Nibbixwoud, the Netherlands | |||
| Year of construction: | 1999 | |||
| Number of storeys: | 5 | |||
| Heated floor area (m2): | 1 500 | |||
| % of total floor area (%): | 100 | |||
| Design outdoor temperature (ºC) | Heating: | -10 | Cooling: | - |
| Design indoor temperature (ºC) | Heating: | 20 | Cooling: | 25 |
| Degree days | Heating: | 3,2601 | Cooling: | No data |
| Base temperature for degree days (ºC) | Heating: | 182 | Cooling: | No data |
2 and not counted above 15.5°C outside temperature
Heating and cooling
| Application: | Space heating, free cooling | |||
| Heat pump type(s): | Brine/water | |||
| Heat pump installed capacity (kW) | Heating: | 15 | Cooling: | Free cooling |
| Refrigerant: | R290 | |||
| Heat source | Energy piles | |||
| Details (circulating pumps): | Ground source 175 W, building main-circulation 175 W, heat pump circulation 50 W, boiler (pump + fan) 300 W | |||
| a) Type of ground heat exchanger: | Energy piles with double U-tubes | |||
| b) Borehole depth (m): | 14 | |||
| c) Pipe length (m): | 336 (total borehole) | |||
| d) Heat transfer fluid: | Brine | |||
| e) Flow rate (l/h): | 2 500-3 000 | |||
| Distribution system(s): | Floor integrated system and ventilation air | |||
| Supply and return temperature (ºC) Summer (S) and winter (W) operation |
Heating: | 35/30 | Cooling: | 19/22 |
| Auxiliary system: | Gas-fired condensing boiler | |||
| a) Size (kW): | 32 | |||
| Fuel: | Natural gas | |||
| c) Operating regime: | 72 h during heating season 2000/2001 | |||
| Heat pump design: | 40% of the maximum load | |||
| Supplementary system: | The same gas-fired boiler above is used for a small amount of DHW (not monitored) | |||
| Heat pump system completion date: | 1999 | |||
Performance
| Heating energy | Heat pump | Aux. heating system1 | Auxiliaries |
| Energy input (kWh/year): | 7 300 | 2 180 | 2 040 |
| Energy output (kWh/year)2: | 37 610 | 1 970 | n/a |
| Energy cost (EUR/year): | 663 | 76 | 185 |
| Cost tariff (EUR/kWh): | 0.09 | 0.34 EUR/m3 | 0.09 |
| Cooling energy | Heat pump | Aux. heating system1 | Auxiliaries |
| Energy input (kWh/year): | 0 | 0 | 710 |
| Energy output (kWh/year)2: | n/a | n/a | 6 350 |
| Energy cost (EUR/year): | n/a | n/a | 64 |
| Cost tariff (EUR/kWh): | n/a | n/a | 0.09 |
2 Measured data
| DHW | Not monitored |
| Coefficient of performance (COP) | |
| Heating: | 5.15 (seasonal average) |
| Test conditions: | 28°C condenser out/ 0°C evaporator out/ 3°C evaporator in. Carnot-efficiency (based on a secondary media) between 0.46-0.50 |
| Cooling: | 8.9 (free cooling) |
| Test conditions: | - |
| Heat pump cost breakdown | No data |
| Alternative system (if has been considered) | No data |
| Fuel cost | No data |
| Payback | No data |
| CO2 emissions |
Heat pump system: 6,730 kg CO2 (electricity) + 490 kg CO2 (natural gas boiler). Total: 7,220 kg CO2/year. Conventional HVAC system: 99,810 kg CO2 (natural gas) + 2,020 kg CO2 (electricity). Total: 11,830 kg CO2/year. Assumptions:
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Operational experience and other comments
The operating experiences have been very good and the comfort in the building has been perceived as good since the commissioning.
The amount of energy for heating and cooling in the ground-source system is not balanced. In the future a shortage of available heat from the energy piles might occur at the end of the heating season.
The project has shown that one should select high quality heat pumps, use pumps with a variable flow and pay attention to the control equipment.
Contacts
|
Contact 1: |
Charles Geelen |
| Company: | TNO-MEP |
| Role: | Information; monitoring |
| Address: | Postbus 342 Laan van Westenenk 501 7300 AH Apeldoorn THE NETHERLANDS |
| Telephone: | + 31 55 549 3103 |
| Fax: | + 31 55 549 3740 |
| Email: | g.p.j.m.geelen @ tno.nl |
| Last updated: 1 March 2004 |
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