SUCCESSFUL RETROFIT OF NON- RESIDENTIAL BUILDINGS: HEATING AND COOLING CONCEPTS Dr.-Ing. Doreen Kalz Fraunhofer-Institute for Solar Energy Systems ISE Symposium IEA SHC Task 47 Frankfurt, 3. April 2014 www.ise.fraunhofer.de
Holistic Evaluation of Concepts Energy Use Energy Efficiency Thermal Comfort OCCUPANT high working place quality (thermal, acoustic, visual) objective / BUILDING reduced heating and cooling energy demand HVAC high plant efficiencies 2
Cross-Comparison Delivered energy use: heating delivery energy use for heating [kwh end /m²a] 250 225 200 175 150 125 100 75 50 25 BEFORE DESIGN MEASUREMENT MEASUREMENT 0 DEN AT GER01 GER02 GER03 3
Cross-Comparison Delivered energy use: total building delivery energy use for total building [kwh end /m²a] 250 225 200 175 150 125 100 75 50 25 BEFORE DESIGN MEA1 MEA2 0 DEN AT GER01 GER02 GER03 4
Cross-Comparison Primary energy use: total building primary energy use for total building [kwh prim /m²a] 450 400 350 BEFORE DESIGN MEA1 300 MEA2 250 200 150 100 50 0 DEN AT GER01 GER02 GER03 5
UBB LAB KKS KKS KWI LTU WIE THI KFW REB DEN DEN DEN AT AT AT GER1 GER1 GER1 GER2 GER2 GER3 GER3 GER3 NIZ NIZ ZUB ZUB GMS GMS GMS SOL SOL ISE ISE ISE DBN DBN LAM LAM POL POL KFW KFW KFW ENG ENG ENG ENG TMZ TMZ SIC SIC SIC UBA UBA BAR BAR HdR HdR SDH SDH SDH SHD Cross- Comparison Germany End energy use for heating cross-comparison of buildings IEA buildings reach very ambitious aims according to heating end energy use 6 delivery energy use [kwh end /m²a] 250 225 200 175 150 125 100 75 50 25 0 250 225 200 175 150 125 100 75 50 25 0 NEW mean 60 kwh/m²a RETROFITTED mean 88 kwh/m²a 250 225 200 175 150 125 100 75 50 25 0 *not included in mean value IEA mean 52 kwh/m²a before after
Holistic Evaluation of Concepts Energy Use Energy Efficiency Thermal Comfort OCCUPANT high working place quality (thermal, acoustic, visual) objective / BUILDING reduced heating and cooling energy demand HVAC high plant efficiencies 7
Heating Concepts Ground-coupled thermal heat pumps Before After 2 Gas boiler, 250 and 283 kw therm High temperature heating with radiators Natural Ventilation 2 ground-coupled thermal heat pumps each 35 kw therm and 2 gas boilers (2x80 kw therm ) Hybrid ventilation with heat recovery Low temperature heating with radiators 8
AMBIENT AIR ENVIRONMENTAL ENERGY GROUND USEFUL ENERGY WASTE HEAT SOLAR Heating Concepts Ground-coupled electrical heat pumps Before After PRIMARY ENERGY FOSSIL FUELS ELECTRICITY SC BOILER HEATING BHEX HP COOLING MV HR VENTILATION Gas boiler 280 kw therm High temperature heating with radiators Natural Ventilation Electrical heat pump 33 kw therm, use of waste heat from printing workshop, old gas boiler as backup Hybrid ventilation with heat recovery Low temperature heating with radiators and convectors 9
Operation Performance of Heat Pumps Cross-Comparison: analysis of efficiency Cross-Comparison Electrical: 2.4 6.6 Thermal: 0.8 1.3* No significant difference between monovalent and bivalent systems Retrofitted Projects: Electrical: 2.9 Thermal: 1.3 Higher supply temperature influence SPF el SPF Heat Pump SPF Heat Pump System electrical SPF>4 Fraction of Auxiliary Energy for Pumps on Total Use [% therm. * SPF according to VDI 4650, 2 (related to delivered energ, thermal and electrical use) 10 G13
Operation Performance of Heat Pump Systems Cross-Comparison: analysis of efficiency Cross-Comparison Significant electrical energy use for pumps in primary circuit (5 to 20%) Reduction of SPF by 6 to 15 % Retrofitted Projects: Well designed systems with a comparatively low auxiliary energy use for pumps SPF Heat Pump SPF Heat Pump System -6 to -15% electrical SPF>4 Fraction of Auxiliary Energy for Pumps on Total Use [% therm. * SPF according to VDI 4650, 2 (related to delivered energ, thermal and electrical use) 11 G13
Use of Environmental Heat Sink Direct cooling GEOTHERMAL ENERGY AMBIENT AIR surface-near ground water surface nat. / mech. cooling tower ground water ventilation natural and hybrid ventilation dry / wet cooling towers 12
Environmental Heat Sink Air Night ventilation concept before retrofit, 1970s after retrofit Daytime: hybrid ventilation (natural and mechanical) Nighttime: mechanical ventilation > 2 ACH, ventilation slats 13
Environmental Heat Sink Air Night ventilation concept before retrofit, 1970s Daytime: hybrid ventilation (natural and mechanical) Nighttime: mechanical ventilation > 2-3 ACH after retrofit 14
Environmental Heat Sink Air Night ventilation concept 15
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Use of Environmental Heat Sink Direct cooling GEOTHERMAL ENERGY AMBIENT AIR surface-near ground water surface nat. / mech. cooling tower ground water ventilation natural and hybrid ventilation dry / wet cooling towers 17
temperature [ C] Use of Environmental Heat Sink Ground temperatures Summer period: Supply temperature 12-18 C Temperature difference 1 to 4 Kelvin Cooling power 10 40 W/m BHEX 35 2004 2005 30 25 20 15 10 5 0 return -5 ambient air supply -10 Jan Mar May Jul Sep Nov Jan Mar May Jul Sep Nov 18
Use of Environmental Heat Sink Direct cooling: analysis of efficiency Cross-Comparison Direct cooling via bore-hole heat exchangers or groundwater Efficiency between SPF 10 and 20 All systems studied reveal potential for further optimization Temperature difference in primary circuit often smaller 2 Kelvin High auxiliary energy use of primary pump due to high pressure drops within hydraulic system and oversized pumps Retrofitted Projects: Good performance: SPF 10 and 19 SPF 45 Groundwater Grundw asser 40 Ground Erdreich 35 30 25 Target: SPF >20 20 15 10 5 0 0 1 2 3 4 5 6 aux. electrical energy use [kwh el /m²a] 19
LowEx Cooling Systems Cooling with high supply water temperatures SURFACE-NEAR CONDITIONING CONCRETE CORE CONDITIONING FLOOR CONDITIONING CEILING SUSPENDED PANELS retrofit retrofit 20
Radiant Cooling KfW-Bank Frankfurt/Main Arch. RKW, Düsseldorf 21
Radiant Cooling Suspended Panels 23 C Cooling panels with phase change materials 29 C 22
efficiency (SPF) efficiency (SPF) Cooling System Impact on auxiliary energy use for pumps considerable auxiliary energy use for distribution and delivery reduction of energy efficiency: approximately 50 % cooling energy [kwh/m² TABS a] cooling energy [kwh/m² TABS a] 40 18 40 35 16 16.8 35 30 14 30 10.0 25 12 25-50% 10 20 20 8 8.1 15 15 5.1 6 10 4 10 5 2 5 0 0 0 I II III IV I II III IV 18 16 14 12 10 8 6 4 2 0 23
Holistic Evaluation of Concepts Energy Use Energy Efficiency Thermal Comfort OCCUPANT high working place quality (thermal, acoustic, visual) objective / BUILDING reduced heating and cooling energy demand HVAC high plant efficiencies 24
Thermal Comfort according to DIN EN 15251 2 Comfort models Static model (PMV) Adaptive model EGU, 2005 operative room temperature [ C] 30 28 26 24 22 20 18 0 5 10 15 20 25 30 ambient temperature [ C] operative room temperature [ C] 30 28 26 24 22 20 18 0 5 10 15 20 25 30 ambient temperature [ C] 25
Thermal Comfort according to DIN EN 15251 Summer Local Comfort Evaluation Global Comfort Evaluation Higher supply water temperature of 18 C surface temperature 21 C Low vertical temperature differences Thermal comfort class II achieved according to adaptive model High influence of occupants 26
Thermal Comfort according to DIN EN 15251 Monitoring and optimization Global Comfort Evaluation Continuous monitoring of HVAC, building and interior room conditions Performance of cooling system and thermal comfort could be improved 2008 86% 2010 98% 27
Holistic Approach of total building s performance BEFORE Retrofit AFTER Retrofit 28
Summary and Conclusion Building Use of hybrid ventilation concepts and solar shading Mechanical ventilation systems with heat recovery, if possible Reduction of (specific) heating and cooling loads in order to use LowEx heating and cooling systems in combination with environmental heat sources and sinks HVAC Primary energy consumption using ground-coupled (reversible) heat pumps is lower than conventional systems with gas boilers and compression chillers Use of waste heat is possible when radiant heating systems are applied Directly cooling using environmental heat sinks is very energy-efficient Auxiliary energy use for pumps and fans needs to be considered 29
Thank you very much for your attention! Fraunhofer-Institute for Solar Energy Systems ISE Dr.-Ing. Doreen Kalz www.ise.fraunhofer.de doreen.kalz@ise.fraunhofer.de 30