Page 173 - AGC_EN_iBook

173
Heating
Cooling
Heating
Cooling
Standard conditions under eN 14511-2
10/7 – 30/35°C
23/18 – 30/35°C
average conditions for the project
12/8 – 30/35°C
20/15 – 30/35°C
Coef cient of performance COP/eeR
4.20
5.00
4.35
4.00
For free cooling, the dry cooler works on outside air (20/15°C), and rejects hot air from the heat pump in cooling mode (35/30°C).The performance details of the water/water heat pump are listed below in Table 1.
ground is used during periods when the average outdoor tempera- ture (averaged over the day) is higher than 14°C. Free cooling via the thermally active slab covers 5% of all cooling needs, in particu- lar at high outside temperatures.
Free cooling via outside air takes place when the outside tempera- ture enables the cold water distribution loop temperature to be reached without using the heat pump (outside temperature
≤ 14°C). A total of 65% of free cooling via outside air is done between 21:00 and 6:00 (storing the cold in the slab).
Free cooling via outside air covers 55% of the cooling needs.
The air handling units treat the supply air at 17°C in heating mode, and at 21°C in cooling mode. Recovery of heat, cold and humid- ity is realised with a heat exchanger wheel (heat recovery when the outside temperature is < 12°C, cold recovery when the outside temperature is > 25°C, with sensible ef ciency of 70%, and a latent heat ef ciency of 25%). Air ow in the of ces is at a constant ow rate, while in the restaurant and meeting rooms it is controlled by a CO2 sensor.The operating modes of the heating coils (35/30°C) and the cooling coils (20/15°C) are the same as in the hot and cold water distribution loops.
table 1. Performance of the water/water heat pump
the climate control system
The hot water distribution loop operates at a ow temperature of 35°C and feeds the coils in the air handling units and the convec- tors (heating).
The cold water distribution loop operates at a ow temperature
of 15°C and feeds the convectors (cooling), the coils in the air hand- ling units and the thermally active slab. Cold water only circulates in the slab between 21:00 and 6:00, owing at a constant rate,The water temperature depends on the zone air temperature (Figure 1).
The convectors (hot, cold) are controlled locally by thermostats. The heat pump generates heat (base production) when the outside temperature is ≤ 14°C. For peak production, a condensing boiler
is available.The water/water heat pump operates at an average
of 35/30°C (the distribution loop) – 12/8°C (ground).The minimum temperature in the distribution loop is 2°C (running with a 30% glycol solution). heat pump power (for heat production) is limited to 12 W/m2.
Free cooling via the thermally active slab is a way of realising the annual energy balance of the ground. In an average year, utiliza- tion of the ground is equilibrated when the free cooling from the
energy balance
Heat pump – cooling (dry cooler) (electricity)
Heat pump – ground (electricity)
Pumps – building (electricity)
Indoor lighting (electricity)
Parking lighting (not yet available)
Fans (electricity)
Boiler (gas)
Humidi cation (integrated)
Primary energy (building)
Compensation through PV electricity generation
Crystalline PV panels (111 kWh/m2.a)
2.40 [kWh/m2.a]
0.46 [kWh/m2.a]
4.30 [kWh/m2.a]
10.63 [kWh/m2.a]
Primary Primary factor balance
2.63 11%
2.63 2%
2.63 19%
2.63 47%
0.0 [kWh/m2.a] 2.63
4.24 [kWh/m2.a]
1.65 [kWh/m2.a]
2.63 19%
1.00 3%
0.0 [kWh/m2.a] 1.00
59.59 [kWh/m2.a]
22.65 [kWh/m2.a]
0.204 [m2/m2]