a micro-heat pump combined with mechanical …[email protected] 1 a micro-heat pump...
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A micro-heat pump combined with mechanical ventilation including heat recovery - simulation
and in situ monitoring
Georgios Dermentzis, Dipl.-Ing.Fabian Ochs, Dr.-Ing
Wolfgang Feist, Uni.-Prof.
Unit for Energy Efficient Buildings University of Innsbruck, Austria
17/5/2017
Outline
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1. Concept
2. Simulation models - calibration & validation
3. Simulation study
Concept
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MVHR preheater
J, f
micro-HP
exhaust
ambient
supply
extract
Electricradiator
Heating Fresh air - Ventilation
Energy efficiency in the building sectorEuropean project iNSPiRe:Development of Systematic Packages for Deep Energy Renovation of Residential and Tertiary Buildings including Envelope and Systems
Integrated into a prefabricated facade
Micro-HP functionality and monitoring
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Monitoring8 temperature sensors1 humidity sensor3 electricity meters2 pressure different sensors (to measure volume flows)
[Ochs et al. 2014]
Demonstration building with the micro-HP
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GroundFloor
Firstfloor
Cellar Unheatedcellar
AtticfloorStair
s
m-HP
Ludwigsburg, Germany
m-HP
comfort sensors (blue dots)
[ Leonardi 2015]
[WB-L]
Monitoring and prediction of annual performance
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First year of monitoring (winter 2015/2016):• Monitoring of micro-HP started in Feb. 2016
Þ no complete winter• Bottom and top neighbor flats were renovated also from inside
Þ unoccupied and unheated flats with low indoor temperatureVery specific boundary conditions
Annual dynamic building and system simulations were performed
Simulation models
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Mechanical ventilation with heat recovery:
Jexh is calculated using the equation 𝑛"#$% = ()*+,()*-.
/0123̇567
()*+,(138
Jsup is calculated with enthalpy balance
(according to PHI definition)
Simulation models
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Heat pump:A performance map model is used based on laboratory measurements for hygienicvolume flow (120 m3/h) including transfer function for modelling the dynamicbehavior (when heat pump or condenser switches on and off):
[ Magni 2015][ Magni 2015]
250
350
450
550
650
50 70 90 110 130 150
P m-H
P/
[W]
Frequency of compressor / [Hz]
3.0
3.5
4.0
4.5
5.0
50 70 90 110 130 150
COP / [-]
Frequency of compressor / [Hz]
-405
$amb / [ C]
Calibration of dynamic behavior of the heat pump
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04:30 04:45 05:00 05:15 05:30 05:45 06:0015
20
25
30
35
40J
sup1
/ [°C
]
04:30 04:45 05:00 05:15 05:30 05:45 06:000
1
2
Ctrl d
efros
t
Time / [HH:MM]
measuredt = 200t = 300t = 400
~20 min
Validation
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Two parameters are compared for the validation:
– Electricity consumption of the compressor
– Temperature after condenser (Jsup1)
Validation – comparison of electricity consumption of the compressor
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00:00 06:00 12:00 18:00 00:000
50
100
150
200
250
Powe
r / [W
]
Time / [HH:MM]
meassim
A day in February with 15 minutes average values
Validation – comparison of supply air temperature (Jsup1)
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00:00 06:00 12:00 18:00 00:0015
20
25
30
35
40
q / [°C
]
Time / [HH:MM]
meassim
A day in February with 15 minutes average values
Simulation study
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Annual dynamic simulations were performed using the validated models
Two parameters were varied:– Set point temperature of the flat and its neighbouring flats – Minimum operation time of the micro-HP
Seasonal performance factors
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Micro-HP performance:𝑆𝑃𝐹<,$= =
>6?2@)2A)BC)D_6?37B)AA?B
Micro-HP system performance:
𝑆𝑃𝐹FGF = 𝑄IJKLMKFMN + 𝑄PJFQRMSQMN + 𝑄TSQRNSLUSQJN
𝑊MW_IJ<PNMFFJN +𝑊MW_PJFQRMSQMN +𝑊MW_TSQRNSLUSQJN
MVHR + micro-HP system performance:
𝑆𝑃𝐹QJQ = 𝑄"#$% + 𝑄IJKLMKFMN + 𝑄PJFQRMSQMN + 𝑄TSQRNSLUSQJN
𝑊MW_"#$% +𝑊MW_IJ<PNMFFJN +𝑊MW_PJFQRMSQMN +𝑊MW_TSQRNSLUSQJN
Simulation results - varying set point temperature
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Parameters Results
Case
Jset of ground floor flat / [°C]
Jset of neighbor flats / [°C]
HD / [kWh/m2a] SPFm-HP SPFsys SPFtot
A(ref) 20 20 8.5 3.6 2.11 4.0B 21 21 12.1 3.5 2.14 3.8C 22 22 16.4 3.4 2.12 3.6D 21 20 20.7 3.2 2.11 3.3E 22 20 38.1 3.1 1.77 2.6
High contribution of post heater
0 50 100 150 200 250 300 3500
0.2
0.4
0.6
0.8
1
Time / [days]
P / [
kW]
m-HP & Post-H & El.radm-HP & Post-Hm-HP
Case C: Jset = 22°C
Max power of approximately 900W
Post heater is in operation about 5 days
Simulation results - varying the minimum operation time of the micro-HP
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Minimum operation time / [min]
Wel_comp / [kWh/a] SPFm-HP
15 273 3.43
30 272 3.48
60 271 3.57
90 271 3.60
• The electricity consumption remains the same• The supplied heat to the flat is increasing leading to better SPF
No significant benefit to increase the minimum operation time on the system performance but benefit with respect to life time
Preliminary monitoring results (year 2)
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• Analysis of monitoring data for the winter 2016/2017 is on going– Preliminary results show relative good agreement with the simulation results
Parameters Results
Case
Jset of ground floor flat / [°C]
Jset of neighbor flats / [°C] HD / [kWh/m2a] SPFm-HP SPFsys SPFtot
A(ref) 20 20 8.5 3.6 2.11 4.0B 21 21 12.1 3.5 2.14 3.8C 22 22 16.4 3.4 2.12 3.6D 21 20 20.7 3.2 2.11 3.3E 22 20 38.1 3.1 1.77 2.6Winter 16/17 21.4 19.3 / 20.7 12.0 3.5 2.14#) 3.3#)
#) Bath radiator not included
Conclusions
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• Concept: an exhaust air heat pump combined with mechanical ventilation with heat recovery is presented, and tested in a demonstration building
• Simulation models are developed, calibrated and validated using on-situ monitoring data
• Building and system simulations are performed to prove the feasibility of the concept and to investigate its performance
– Varying the set point temperatures of the investigated flat and its neighbouring flats:
• Total SPF (including MVHR) varies between 2.6 and 4• System SPF (excluding MVHR) was 2.1 with moderate use of post heater• SPF of the micro-HP varies between 3.1 and 3.6
– The influence of minimum operation time of the compressor is negligible on the performance of the system but may increase the life time of the compressor
Outlook
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Future work will concentrate on – Individual room control– Further performance improvement
See also Poster: Session 1.3 & 1.4 NZEB, P.1.3.5 Fabian Ochs , Rainer Pfluger, Georgios Dermentzis, Dietmar SiegeleEnergy Efficient Renovation with Decentral Compact Heat Pumps
visit iNSPiRe website
http://inspirefp7.eu
This document has been produced in the context of the iNSPiRe Project.
The research leading to these results has received funding from the European Community's SeventhFramework Programme (FP7/2007-2013) under grant agreement n°314461. All information in this document isprovided "as is" and no guarantee or warranty is given that the information is fit for any particular purpose. Theuser thereof uses the information at its sole risk and liability. For the avoidance of all doubts, the EuropeanCommission has no liability in respect of this document, which is merely representing the authors view.
Thank you for your interest
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Special thank for the support of:Wohnungsbau LudwigsburgVaillantGumpp&MaierSiko Energiesysteme