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Oaknoll Spring Street Senior Living Facility - Mech

Challenge

As it continues to grow, offering independent living, assisted living and health center facilities, Oaknoll was in the midst of its largest expansion project to date: adding the Spring Street Senior Living Facility to its campus.
 
The property’s owner and residents of this building were interested in an HVAC solution that would offer cost savings and energy efficiency. Residents also wanted to have as much temperature control as possible over each of the different rooms within their apartments.
 

Solution

After comparing different heating and cooling options – including VAV and VRF systems – to determine potential energy savings, fastest return on investment, and highest upfront costs, it was determined that a geothermal system would provide the energy and economic savings that Oaknoll and its residents hoped for.
 
Because most of its land is covered by buildings, Oaknoll didn’t have a lot of ground to work with – but, working closely with the City of Iowa City and Johnson County, Shive-Hattery was able to design a geothermal heating and cooling system by drilling four wells on the property.
 
Wells pump water out of the ground and into the building. From there, heat is removed from the water if heating is needed; heat is put back into the water and then back into the ground if heat needs to be removed from the building. Removing heat from the building and putting it back into groundwater (which is normally around 55 degrees F) is more efficient than rejecting it to outside air, which may be around 85 degrees F (or warmer).
 
When water is taken out of the ground, it runs through the heat recovery chiller, which makes hot water for the radiant floor heat or chilled water for the building’s air-conditioning units. The heat recovery chiller also allows Oaknoll to remove heat from areas that need to be cooled and recirculate it back to areas that need heat. This is especially helpful in the spring and fall months when simultaneous heating and cooling may be needed.
 
For each apartment’s bathroom ventilation, an energy recovery air-handling unit handles outside air and exhaust air for the building. The energy recovery wheel inside the unit transfers energy from the exhaust-air airstream to the outside-air airstream, and preconditions the air.
 
An in-floor radiant heat system in each apartment circulates hot water through tubes. The thermostats in each room control the hot-water flow through the tubing. To provide as much temperature control as possible, each apartment is split into different heating zones, allowing occupants to control the heat in their bedrooms separately from heat in their living rooms.
 

Impact

The Spring Street Senior Living Facility addition allows Oaknoll to continue to care for Iowa City’s senior population. The geothermal system helps the retirement community be responsible in terms of finances and environmental impact.
 
Individual temperature control in each Spring Street Senior Living Facility apartment allows residents to control the heating levels in their bedrooms separately from living room heat for customized comfort.
 
The investment in a geothermal system also qualified Oaknoll for a $940,000 utility rebate, making for a fast return on investment and allowing the retirement community to redirect those savings toward other important care initiatives.
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