Hybrid Energy Systems in Future Low Carbon Buildings
 
Scope  
Background  
Design concept  
Hybrid concept  
Methodology  
Modelling tools  
Case study results  
Electricity demand (appliances-DHW)  
Thermal demand (ESP-r)  
Pv-wind supply (homer)  
Physical integration  
Annual evaluations  
Hourly evaluations  
Environmental impact  
  



CASE STUDIES - CONCLUSIONS
  • Two low-carbon building designs have been developed for a northern (Glasgow) and southern European (Palermo) climatic region - both are shown to operate as net-zero-energy buildings.
  • A customized excel-based tool has been developed to collate process and display simulation data.

  • Financial analysis reveals that incentives (FIT and RHI) are necessary for renewable energy systems to be viable in our 2 case studies.

    • Glasgow building
      • We have considered an insulated, lightweight building with 56 % (optimized) glazing to south façade area.

      • Demand reduction measures are applied in order to achieve a heating demand of 8.2kWh/m2.

      • Summer overheating is eliminated through the use of fixed shading and ambient cooling (2 ach are required on summer nights).

      • A hybrid combination (PV/ solar collector/ GSHP) connected to a storage tank at a low temperature of 45oC is required to cover total heat and power demands.

      • PV installation consists of 25 panels which require an area of 31m2 on a 40° pitched roof and provides a 4.35 kW power output (not viable without adequate feed-in tariff and grant).

      • Solar collectors cover 47% of DHW demand and require an area of 3 m2.

      • Small-wind is not adequate due to low energy yield.

      • Seasonal storage is not applicable.


    • Palermo building
      • We have considered an insulated, heavyweight building with shaded south facing glazing and high albedo external surfaces.

      • Demand reduction measures (use of thermal mass/ ambient cooling - 5ach during summer nights/ shading) are applied in order to achieve a cooling demand of 3.6kWh/m2.

      • Heating demand is eliminated via MVHR and passive solar gains.

      • Switching controls off leads to a maximum indoor temperatures of 29°C which could be considered acceptable for a short period of time.

      • Our system includes a hybrid combination of PV, solar collectors with a small direct electric heating coil.

      • PV installation consists of 12 panels which require an area of 15m2 on a 30° pitched roof and provides a 2.1 kW power output (not viable without adequate feed-in tariff).

      • Solar collectors cover 87% of DHW demand and require an area of 3 m2.

      • Small-wind is not adequate due to low capacity factor.

      • Ground duct ventilation has been investigated but not applied due to economical viability.

      • Seasonal storage is not applicable.