Building services installation Sustainable retrofitting of buildings- Sub module 3
District heating Towards lower temperature on primary side
New demands to secondary side Prerequisits Low flow temperature Low return temperature Potential to add local produced heat from renewable energy sources and heat recovery Solutions Decentral hot water preparation Larger radiators and convectors Mixing loop/shunt
Connecting district heating directly to central heating system Distribution pipes in basement Room heating, supply Room heating, return Outdoor temperature sensor Energy meter District heating connection in basement, block 13
Simple solution for add-on of local energy source Distribution pipes in basement Heat pump Outdoor temperature sensor Buffer tank Energy meter District heating connection in basement, block 14 and 15
Hot water is produced in the individual apartments. (Micro heat exchanger) Flatstation Possible shunt Possible shunt Floor heating Room temperature thermostat Return flow temperature thermostat Energy and waterflow are connected to BMS Connection to room heaters Regulation valves are dynamic Principal diagram for connection of room heating and water heating in each apartment for Trigeparken block 13-15
Optimized flatstation (Instantaneous water heater) from Danfoss Advantages designed for low temperature DH insulated to lowest heat loss in market superefficient heat exchanger HEX cold HEX under idle load e save TM integrated differential pressure control no circulation of hot water max 4 l vol.in pipes stainless steel no limestone fouling no legionella 32,3 kw DHW
Low temperature district heating system pros and cons Advantages Heat loss is reduced leading to significant economical savings for district heating company and perhaps district heating customer If the heat is produced on a combined heat and power plant (CHP), the electrical efficiency will be improved Disadvantages Old district heating pipes might need to be changed Heaters in houses might not have sufficient capacity when using lower temperatures in the central heating system.
Ventilation and heat recovery Växjö, Sweden New balanced ventilation Heat recovery Exhaust air Attic Ventilation unit Supply air Appartement
Ventilation and heat recovery
Ventilation and heat recovery Växjö, sweden Before renovation: Calculated savings 40 4 = 36 kwh/m2 ( 90%)
Ventilation princip for Trigeparken. Exhaust air is led to the roof through vertical ducts in technical shafts Air is extracted from bathroom and kitchen Fresh air is distributed to each room through ducts Ventilation unit with heat recovery and fans All ducts are insulated with 50 mm to avoid risk of condensation and heat loss Fresh air intake from facade
Most important specifications for ventilation system in Trigeparken Max. pressure loss for ducts: 0.8 Pa/m Max. electricity consumption (SFP) for complete ventilation system: 0.8 kj/m³ Heat recovery of min 86% (Temperature efficiency) To save electricity, the heat recovery unit will be bypassed when outdoor temperature is above 17 C Air flow is demand controlled through humidity sensors. Alarms are triggered, when filters are congested. Demand controlled ventilation can save up to 30% on electricity consumption for fans. In the Swedish dwelling project Isbanan in Helsingborg, electricity savings have been measured to 0.6 kwh/m²/year and heat savings to 0.13 kwh/m²/year
Central vs. decentral ventilation Lower electricity consumption with decentral ventilation Decentral ventilation requires more ventilation units, which normally will require more maintenance With decentral ventilation, the users can have the possibility of controlling their own ventilation unit Troubleshooting can be more time demanding with decentral ventilation, as there are more ventilation units, which might require access to the apartments Yearly access to apartments can also be an advantage.
Waste water heat recovery Växjö,Sweden Heat exchanger polymeric material
Waste water heat recovery - heat exchanger Evertech-heat exchanger Patented design with polymeric material Non-corrosive Standard couplings Low weight
Waste water heat recovery special house, Växjö, Sweden Alabastern area, Växjö 39 appartments 76 MWh thermal energy Waste water from appartments ; + 21 C; 3300 m3/year Waste water heat recovery system Waste water to sewer ; + 6 C 17 MWh electric energy Calculated savings 45 31 = 14 kwh/m2 ( 30%)
Waste water heat recovery System in Trigeparken, Aarhus Terrain Closed circuit with an water/glycol mixture connected to heat pump placed in installations room. Temperaturset around 5/10 o C Existing drain pipe Clamp for placement of sensors Heat pump Hot water tank Layer of coated Leca for insulation against the cold soil Sewage water Pump (must be able cope with diapers, tissues, toilet paper etc) 2.5 m Heat exchanger Heat pump cools the closed circuit and transfer the extracted heat to the hot water tank
Waste water heat recovery System in Trigeparken, Aarhus New collecting well for collecting sewage water is placed on existing drain pipe Existing drain pipes
Waste water heat recovery simulation results The waste water heat recovery system is expected to cover about 75% of the heat needed for hot tap water consumption COP is expected to be 4,3 Heat pumps are in the range of 7-10 kw pr. unit Each heat pump recover from 27 36 appartments pr. unit
Waste water heat recovery Existing system in Aarhus Drain pipe leading sewage water to well Pipe med pump (submerged in the sewage water) pumping sewage water away from well Heat exchanger
Waste water heat recovery Existing system in Aarhus
Domestic hot water Alabastern, Växjö, Sweden Individual monitoring!
After: Domestic hot water Växjö, Sweden Before NYD20:
The integrated total system Växjö, Sweden The integrated total system The control system Monitoring etc.
Lithium Balance Battery Systems approach 7. Remote and advanced battery diagnostics to optimise battery life and reduce service costs Cloud BMS BMS 1. Functionally safe BMS that allows advanced diagnostics 6. Use price, weather and load forecasts to time charge/discharge and reduce energy costs Forecasts Cloud EMS BESS Rack 2. Certified and cost competitive BESS rack 5. Enable DSO remote control Grid Support Energy Asset Control BESS controller 3. Time charge/discharge and reduce inverter power loss to reduce energy costs
Market trends for batteries Big potential market for large battery energy storage systems Capacity increase by a factor 14 expected worldwide the next 7 years Residential: 35% price decrease in 3 years, 20% price decrease the next 2 years Reference :BATTERY STORAGE FOR RENEWABLES: MARKET STATUS AND TECHNOLOGY OUTLOOK 2015, http://www.irena.org/documentdownloads/publications/irena_battery_s torage_report_2015.pdf Reference : ees Europe: Falling prices boost energy storage, PV Europe, 15/5/2017, http://www.pveurope.eu/news/energy-storage/ees- Europe-Falling-prices-boost-energy-storage
Battery systems for PV Denmark vs. Sweden Increased self-consumption gives better economy for PV system owners Relevant for private owners, housing associations and businesses With a PV Battery System the self-consumption increases from approximately ~30% to 80%
Battery systems for PV - Maximized self consumption Sunny day Morning: battery is rapidly charged in the morning and hereafter PV power is exported Evening: stored power is gradually released so import/export is balanced at almost zero
Lower electricity prices Example on avg. electricity price for a Danish housing association: kr/kwh Grid only: 2,25 Grid + PV: 1,75 Grid + PV + Battery: 1,62 Calculation model by COWI developed in Elforsk-project Boligejendomme med CO2 neutralt elforbrug
Battery Systems implementation for READY 43kWh battery rack Space for 5 racks 50kW ABB inverter Space for an additional inverter Low power free cooling system Alarm system
Advanced testing and control The Controller: Controls up to 32 BESS Racks Manages charge/discharge Controls other energy assets such as heat pumps and EV chargers to reduce energy cost at the site Facilitates remote DSO control Partnership with ABB The inverter is the main source of energy loss 60% of the time the battery inverter is in standby mode 30% of the power loss is due to standby Developed new inverter SW that allows LiBAL BESS Controller to manage the inverter for more intelligent standby aggregation
PVT module from Racell PV = PhotoVoltaic (Solar cells) for electricity production T = Thermal for heat production
Cross section of PVT modules
How much of the solar energy (1000 W/m²) can be converted to usable power? Existing commercial products and systems only (rough numbers): PV cell electricity Heat Collector heat energy 15-20% 50-80% 170 W/m ² 650 W/m 2
Example of installation
PVT modules placement in Trigeparken 56 m 2 PV modules on the roof of gable of block 12 286 m 2 PVT modules on the roof of block 12 217 m 2 PVT modules on the roof of block 11 217 m ² PVT modules on the roof of block 11 oo oo o o
PVT module system for Ringgaarden
PVT simulations on system performance PVT modules for heat pump. Performance as a function of the PVT area. Valid for one block. Performance at full load from PV part PVT area 220 110 m² Solar thermal energy to the system 34.842 33.767 kwh/year Electricity production 29.863 16.208 kwh/year Thermal production per m² PVT 158 307 kwh/m²/year Electricity production per m² PVT 136 147 kwh/m²/year Balance Demand for hot tap water 47.700 47.700 kwh/year Circulation loss 6.000 6.000 kwh/year Heat from heat pump 36.100 36.600 kwh/year District heating 11.000 12.500 kwh/year COP 4,1 4,0
PVT modules simulation results The heatpump and PVT module can cover 75% of the heat needed for domestic hot water demand The PVT module can in combination with the battery cover 100% of the electricity demand for the heat pump. The rest of the electricity produced will be used by the common facilities (lights, clothes washing etc.)
Summary Building services installation - heat Both central and decentral heat distribution is used in Ringgaarden Waste water heat recovery/pvt modules with heat pump can cover about 75% of the heat needed for domestic hot water Low temperature heating can be implemented without changing the radiators and convectors District heating temperature can be lowered from 80 to 60 C
Summary Building services installation - electricity In Denmark, as much electricity as possible produced by PV should be used for self consumption Without batteries, 70% of the electricity produced will be sold to the grid With the batteries, 20% of the electricity produced will be sold to the grid Demand controlled ventilation can save up to 30% on electricity consumption
Contacts Morten Christensen mnsc@cowi.com Ph. 5640 7187 / 4176 7187 Reto Hummelshøj rmh@cowi.com Ph. 5640 2766 / 2964 7160 Stefan Olsson Stefan.olsson@energikontorsydost.se +46 709 890181