Congratulations to the Great Installations Challenge Winner, Al Wallace and Energy Environmental Corporation! IGSHPA and Grundfos have selected Hill Country Hacienda in Kerrville, Texas, as the winner of the Great Installations Challenge!
The Hill County Hacienda project is a heating and cooling system for a 30,000 square feet private residence with geothermal heat pumps providing radiant floor heating and cooling with supplemental air cooling served by a 40 ton vertical ground heat exchanger (GHEX). The radiant floor cooling utilizes passive GHEX fluids directly for in-floor cooling with a COP exceeding 50.0 based on the efficiency of Grundfos ECM circulators without using a compressor to chill water. A central mechanical room with the GHEX pumping delivers 120 GPM of ground source fluids to 14 water-water and water-to-air heat pumps distributed in five mechanical rooms throughout the complex. The WaterFurnace heat pumps are state-of-the-art and incorporate 7 Series variable speed (VS) compressor heat pumps for supplemental cooling with automatic humidity control, high temperature water-water heat pumps for domestic hot water, radiant floor heating and cooling and 7 Series VS split units for distributing air to upper levels with the compressor in the basement level mechanical rooms. The 7 Series heat pumps are configured with Intellizone2 zoning which provides intelligent zoning to up to six separate air zones from one heat pump which varies compressor speed and fan speed to meet the specific zone requirements in real time. The complex uses the WaterFurnace Symphony home automation control which allows for remote operation, troubleshooting, and monitoring of the heat pumps.
What makes this project unique?
The GHEX pumps and heat pumps have been recently upgraded to provide higher efficiency with lower maintenance. The original GHEX pumps utilized 12 UPS26-99 circulators for circulating fluids from six independent GHEX circuits combined to one manifold. From the manifold, 7 UPS 40-240 and UPS 32- 160 circulators distributed the GHEX fluids to the mechanical rooms. Recently this pumping configuration was upgraded to two Magna3 40-180 circulators to circulate fluids to the GHEX using differential temperature control by adding an additional temperature sensor to each Magna3. The campus distribution is served by three Magna3 80-100 circulators set on constant pressure which regulates flow to the heat pumps each configured with a modulating control valve based on compressor speed. The Magna3 pump flow centers and a hydraulic separator were manufactured by Geo-Flo Corporation enabling installation in 10 days by two technicians. The upgraded system provides twice the pumping capacity at one-third the energy use of the original fixed speed pumps and virtually eliminating ongoing GHEX maintenance.
Southwest Texas is very hot and humid. Energy Environmental Corporation (EEC) patented an integrated geothermal-centric radiant heating and cooling architecture which meets the heating and cooling loads in this challenging climate with superior energy efficiency. The cooling and heating system was designed to attain net zero energy performance and installed reducing sensible cooling loads by 70% at a system COP of 6.0. Energy recovery ventilators (ERVs)provide fresh air the residence integrated with the VS heat pumps to deliver high performance and energy efficiency using the ECM fan blowers. Bath fans were eliminated using the ERVs which draw stale air from the bathrooms and inject fresh air into the bedrooms and common areas.
To eliminate the risk of condensation on the floor, precise humidity control is provided by the 7 Series water-air VS heat pumps to maintain the radiant floor above dew point. Energy Environmental Corporation designed four wall-mounted 4’x8’ HDPE radiant distribution panels serving 72 radiant zones which receive hot and chilled water injected from a UPS26-99 to a Magna3 40-80 circulation pump which is set on constant pressure control which modulates flow to each zone based on active zone calls.
A significant electrical energy offset is achieved using two wind turbines on this 1,000 acre ranch. Additional energy savings is realized using high temperature water-water heat pumps configured to provide chilled water while producing the domestic hot water for the residence. The COP of this dual process configuration is 7.0 while reducing the heating load imposed on the GHEX, thus reducing the GHEX size by 15%. Three Grundfos Alpha215-55 HWR-D pumps provide hot water recirculation delivering instant hot water to mechanical rooms located 200 feet from the main mechanical room 1,000
gallons of domestic hot water. When GHEX fluids are below 60 deg. F, the controls bypass the GHEX circulators and directly use ground fluids in the radiant floor cooling system.
Using on-board controls with the Magna3 pumps, system controls are greatly simplified. The Magna3 pumps set on differential temperature or constant pressure need only one closed contact when any heat pump calls in order to deliver GHEX consistently and efficiently. Standard 24VAC controls for each zone thermostat actuate zone valves based on heating or cooling set points. Off-the-shelf Functional Devices panel-mounted RIB relays lock out heating calls when a cooling call exists in order to give priority to cooling which has a longer response time than heating. To assist the owners or maintenance technicians, the main control panel lights in red for active heating, blue for active cooling, and green for power on with no calls. EKM energy meters monitor energy consumption in real time providing technicians the ability to adjust system settings for the highest energy efficiency.