Overview of the Integrated Heating, Cooling, and Ventilation Systems
Heating, cooling, hot water production, and ventilation of the Wallace home is accomplished through Integrated Renewable Energy Systems specially designed by Al Wallace of Energy Environmental Corporation. Solar hot water collectors provide 90% of the hot water for radiant floor heating and domestic hot water use, including a hot tub. A Water Furnace 3.5 ton water-to-water geothermal heat pump helps maintain the set water temperature in the hot water tanks. A water-to-air geothermal heat pump works in conjunction with a Venmar energy recovery ventilator (ERV) to provide air conditioning and ventilation. Geothermal also provides cooling for a wine cellar and "cold pantry" in the kitchen. An EPA approved wood burning fireplace (see below) has been installed in the living room downstairs. In addition, a 6 KW solar PV system provides part of the electricity load for the home. For further discussion on the combination and energy savings of renewable energy systems and power generation in the home, please visit our Integrated Systems page.
Staged Solar Hot Water
For a basic introduction to solar hot water heating and the specific products and system components that are being incorporated into the home, please visit our Solar Hot Water page.
Energy Environmental has designed the solar hot water system design for the home and its integration with radiant floor and ground source geothermal heat pump systems. We installed six 4 x 10 solar collectors on the south facing roof of the home as part of our staged solar design. Staged solar heating is a specialized solar thermal system design which can increase the solar factor from the Colorado average of 0.65 to 0.90, meaning that the solar thermal collectors will provide 90% of hot water needs.
Staged solar heating uses a combination of controllers, temperature sensors, and two to three hot water storage tanks to control water temperature and prevent overheating during summer months while still meeting hot water demands during winter months. A small sized 40 gallon water storage tank will be used as the primary tank. Once a temperature sensor reaches a water temperature of 170 degrees, cool water from a secondary tank will be exchanged with the hot water in the primary tank to reduce the temperature and heat the second tank. If the second tank reaches the high temperature set point, its heat will be exchanged into a third hot water tank. Super heated water produced by the collectors can be directed to laundry, dishwashing, radiant snow melt, and towel warmers. Excess solar heat can be "dumped" to PEX tubing in the foundation piers, which will warm and charge the ground for the geothermal heat pump system.
In addition, a dynamic temperature loop circulates water through the collectors which is activated by a solar PV-controlled pump. This provides an accurate measure of the collector temperatures and prevent the mixing of under temperature water in the storage tank. This is a common problem with typical systems and can bring down the temperature of water in the storage tank, reducing efficiency.
WaterFurnace Geothermal Heat Pumps
Please visit the Geothermal Heat Pump section for a basic introduction to how geothermal heating and cooling works and for a description of the products and components incorporated into the home.
Ground loops from the previous geothermal heat pump system were unaffected by the fire and remain underground. Sizing and system design accounts for the space and water heating needs and cooling needs of the home. Two heat pumps have been installed in the home. One heat pump is a WaterFurnace water-to-water 3.5 ton EW series unit, which augments the solar thermal system when solar is insufficient. The water-to-water pump helps keep the domestic hot water at a constant 120 degrees. The geothermal and solar hot water heats enough water for both radiant heating of the home and domestic hot water use. The second heat pump is a WaterFurnace water-to-air 3 ton Envision unit, which runs in conjunction with a VENMAR ERV unit, providing air conditioning and high indoor air quality. This heat pump can also produce forced air heating to quickly heat the home, but the majority of heating is provided by the combination of solar hot water distributed through a radiant floor system.
Radiant Heating and Cooling
Please visit the Radiant Hydronic section for a basic description of how radiant heating and cooling works. The radiant heating/cooling tubing has been installed and covered with Gyp-Crete Therma-Floor “Green” underlayment to provide environmentally friendly efficiency and comfort. In addition, radiant is used for heating in the garage and may be used for snow melt in the driveway. Special controls help reduce energy use and prevent condensation in the cooling application. An outdoor reset control adjusts the radiant floor heating based on the outdoor air temperature to reduce energy use, and an infrared dew point sensor prevents condensation in the cooling application.
Venmar 4100 Energy Recovery Ventilator (ERV)
Please visit our section on Energy Recovery Ventilation for a basic description of how ERV's work. A Venmar 4100 ERV with HEPA filtration is installed in the home to work in combination with a WaterFurnace water-to-air geothermal heat pump. The ERV refreshes and filters air inside the home without loss of heat or cooling. Because the home is very tightly air sealed and insulated, ventilation is critical to ensure high indoor air quality in the home.
HVAC Products in the Home
Heatilator CONSTITUTION Woodburning Stove
The Constitution is an EPA Phase 11 compliant unit which can be operated in areas with strict air quality regulations or "burn bans" such as Denver. Their high-tech clean burn produces only 3.25 grams per hour of particulate while producing heat outputs of 51,200 Btu's on high setting and up to 11,300 Btu's for up to 10 hours on low setting. EEC has installed this unit in the downstairs living area for occasional use.
Thermaflex EverClean Premium Flexible Duct
Thermaflex is a global leader in the flexible duct product industry for both residential and commercial HVAC applications. EverClean flexible duct us designed for residential applications and has been recognized by both ENERGY STAR and as a GREEN product from the Green Building Pages as a true Green product from manufacturing process to the life cycle of the product. Everclean comes GREENguard certified and features a lifetime warranty to the original homeowner.
EverClean flexible ducts perform well in low to high pressure cooling and heating systems and can be utilized in either supply or return sections. EverClean is anti-microbial, able to resist and inhibit the growth of mold and mildew which helps to improve indoor air quality. The inner liner provides efficient air delivery and will not puncture or tear, eliminating "blow outs" and costly callbacks. The Owens Corning insulation enhances air temperature improving the energy efficiency. EverClean is acoustically rated and a great alternative for hard pipes, having 50% less static pressure than conventional flex duct. All EverClean components are self-extinguishing and will not deteriorate in a fire until the temperature reaches the melting point of glass.
Below: EEC has installed Thermaflex in the conditioned spaces of the home. Running ductwork in conditioned space further reduces thermal losses and improves heating/cooling efficiency.
Speedi-Boot Boot Hanger
Speedi-Boot Boot Hanger saves on HVAC installation time and costs, and delivers improved indoor air quality and energy efficiency in residential and commercial buildings. Designed by HVAC experts, Speedi-Boot hanger is easy to install in two minutes or less, cutting down significantly on labor time. The heavy-duty galvanized metal frame -- complete with foam gasket and construction debris cover -- eliminates boot deformation, fastens securely to reduce loss of energy and intake of poor-quality air, and improves sealing process for one-hour fire rating
Energy Environmental Corporation has installed Speedi-Boot boot hangers in the home in conjunction with ThermaFlex Everclean flexible duct (see pictures below). We are very impressed with the functionality and workmanship of this product. It provides several enhancements over traditional ductwork which are required for LEED certification. These include preventing debris from entering ductwork, providing a positive seal between the duct and the floor or wall, and enhancing the ductwork performance by eliminating sources for leaks at terminal ends. These units make installation much easier and result in high quality performance. We recommend this product to our clients.
Below: Pictures of Speedi Boot installed in conditioned space within the platinum LEED home.