P3. Residential Hydronic System Demonstration > Outcomes

• Mode 1 used about 11 kWh per day with an average peak demand of 1.4 kW occurring after 7 pm. In Mode 1, 14% of the average energy use occurred between mid-night and 11 am. The average outside temperature during Mode 1 was 77.7°F.
  
• Mode 2 used about 4.6 kWh per day with an average peak demand of 1.1 kW occurring just before 7 pm. Cooling performance results revealed that slab pre-cooling in Mode 2 caused about 13% the energy use to shift from on-peak to off-peak hours. The average outside air temperature during Mode 2 was 75.4°F, which accounts from some of the reduction in energy use and average peak demand.
  
• Mode 3, through 9/25/02, used about 9.7 kWh per day with an average peak demand of 1.1 kW occurring just after 4 am. In Mode 3, 72% of cooling energy was used from mid-night to 11 am. The average outside air temperature during Mode 3 was 75.8°F.
  
• During heating season, the energy consumption with hydronic forced-air heating (Mode H1) was similar compared against hydronic radiant slab (Mode H2) heating, with neither mode showing an advantage over the other.

• Residential radiant cooling using exposed floor slabs is an attractive additional feature for marketing radiant heating systems that will also shift energy use to off-peak hours.
  
• Residential night ventilation, used with or without radiant cooling, is also an attractive technology for shifting energy use and demand from on-peak to off-peak periods.