Energy Effort of Air Distribution Systems

Transcription

1 Energy Effort of Air Distribution Systems F. Kolarik

2 Content Introduction Energy effort of air distribution systems Method of calculation Example Further investigations

3 Introduction Increasing requirements regarding living and working conditions Increasing number of industrial and office buildings equipped with VAC-systems Energy generation in district heating and cooling stations Air transport through duct network to the rooms

4 Introduction In ventilation systems air transport cost amount up to 70% of the total operation cost heat and humidity recovery increase share (flow resistance increases) Within the Life-cycle of a ventilation system the installation might change several times (e.g. changing production) network changes additional vans, chillers destribution networks have become more complex (meshed)

5 Introduction Tool for the analysis and the simulation of extended and meshed duct networks is needed Dimensioning of the duct network Choice of the components Hydraulic balancing of the system Tool should also deliver the yearly energy effort for air transport To evaluate different system solutions

6 Determination energy effort of air distribution systems P el. V R or CO 2. V R or CO 2

7 Determination energy effort of air distribution systems First step: Calculation of air volume rates given set point (ϑ R, CO 2 ) Building simulation (TRNSYS) air volume rates for each zone und timestep (file) Second step: Calculation of total pressure losses air volume rates for each zone und timestep Flow resistances Total pressure loss and air volume rate

8 Determination energy effort of air distribution systems Third step: Calculation of energy effort Total pressure loss and total air volume rate Characteristic fan Curve p = f( n, V& ) η = f( n, V& ) Mechanical power at the fan shaft losses of belt drive, motor, frequency converter Total input electrical power Integration over a period (8760 h = 1year) Energy effort of air distributation

9 Example for the simulation of an air duct network zone 5, 10500m³/h zone 4, 5700m³/h zone 3, 4100m³/h zone 2, 8000m³/h central VAC-UNIT m³/h zone 1, 8000m³/h

10 Example for the simulation of an air duct network Distribution of pressure losses 70% 60% 61% Share 50% 40% 30% 20% 16% 16% 10% 4% 3% 0% Central VAC-Unit Fittings (Bends, T-Branching) Inlets, Outlets, Silencers Dampers Component Duct friction loss Air rate controllers

11 Example for the simulation of an air duct network Different operation modes 16 Air volume Zuluftvolumenstrom rate in in m³/h m3/(h*m2) m² KVS 2-stufig Two step time Uhrzeit VVS

12 Example for the simulation of an air duct network energy effort in kwh/year KVS Two step VVS Operation mode

13 Further investigations Calculation of further typical VAC- Systems Different buildings Systems with decentralist vans in the duct network Effects of components E.g. influence of fan drive (belt drive or direct) Build-up a data bank with key data Develop of a simple calculation method energy effort air distribution