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Investigation of energy flows in thermally activated building constructions Part 1: Transferring energy between 2 building zones . Nordic PhD Seminar 08 / 12 / 2011. Jérôme LE DRÉAU. Transferring energy between two building zones. Transferring energy between 2 building zones. Summer
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Investigation of energy flows in thermally activated building constructions Part 1: Transferring energy between 2 building zones Nordic PhD Seminar 08 / 12 / 2011 Jérôme LE DRÉAU
Transferring energy between two building zones • Transferring energy between 2 building zones Summer or sunny days Winter or cloudy days Heating the North side Cooling the South side Jérôme Le Dréau jld@civil.aau.dk
Transferring energy between two building zones • Presentation of the system: capillary tube mats • Very large-area heat exchangers • Low temperature difference can be used • Small time constant Wall Capillary tube • System used for heating • System used for cooling • Thanks to a smart hydraulic layout, possibility of transferring energy between the 2 rooms
Transferring energy between two building zones • Results: Jérôme Le Dréau jld@civil.aau.dk
Nordic PhD Seminar 08 / 12 / 2011 Investigation of energy flows in thermally activated building constructions Part 2: Cooled radiant walls coupled to the room environment Jérôme LE DRÉAU
Cooled radiant walls coupled to the room environment Hypothesis: Cooled radiant walls will remove the heat more efficiently than an air conditioning system. • The different solutions will be compared, combining the analysis of two parameters: • Energy consumption (quantity & quality of the source) • Comfort in the room (quality of the energy delivered) • Finally how to define efficiency… Energy Indoor climate
Cooled radiant walls coupled to the room environment • Methods used: • Simulations (CFD + simulation of energy systems) • Full-scale experiments Contents : How to evaluate the energy consumption? How to evaluate the indoor climate? First results
Cooled radiant walls coupled to the room environment How to evaluate the energy consumption?
Cooled radiant walls coupled to the room environment • Cooled radiant panel: • Very large-area heat exchangers • Low temperature difference can be used • Small time constant Wall Capillary tube
Cooled radiant walls coupled to the room environment • Different ventilation types: • Mixing ventilation • (different types) • Displacement ventilation
Cooled radiant walls coupled to the room environment • What happens in the room? % Ventilation Mini 25% 50% 75% 100% • % Radiant panel • % Radiation • % Convection % Transmission Result: heat balance of the room
Cooled radiant walls coupled to the room environment Different control strategies: high flow rates OR low inlet temperature ACH -> Qfans Tinlet Flow rate -> Qpumps Tinlet With or without cooling Result: energy consumption of the room
Cooled radiant walls coupled to the room environment BUILDING Source 1: Outdoor air Source 2: Groundwater Storage tank Source 3: Sky radiation Source 4: … Result: energy consumption of the building & quality of energy
Cooled radiant walls coupled to the room environment How to evaluate the indoor climate?
Cooled radiant walls coupled to the room environment PMV Additional parameters • Vertical air temperature gradient • Radiant temperature asymmetry • Surface temperatures • Draught rating EN ISO 7730 • Air temperature • Radiant temperature • Air velocity Indoor Air Quality
Cooled radiant walls coupled to the room environment First results
Cooled radiant walls coupled to the room environment • Model used: • Heating case • Outdoor temperature of -12°C • Construction parts (BR10): • External wall: U=0.15W/m2.K • Window: U=1.40W/m2.K • Roof: U=0.10W/m2.K • Ground: no heat losses • Different ventilation rates (0.5ACH – 3ACH) • 100% convective OR 100% radiative (floor) • No air temperature gradient OR Air temperature gradient
Cooled radiant walls coupled to the room environment • Results: Static calculation with heating power kept constant
Cooled radiant walls coupled to the room environment • Results:
Radiant wall coupled to the room environment Jérôme LE DRÉAU PhD fellow Supervisor: Prof. Per HEISELBERG Aalborg University (DK) - Department of Civil Engineering @jld@civil.aau.dk +45 50 30 01 37 Thank you for your attention!