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March 23, 2017
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The Mill at Dover-Foxcroft

LG’s VRF System Delivers Total Tenant Comfort in Mixed-Use Mill Complex and Integrates Seamlessly with Water-Source Geothermal System for High Energy Efficiency

The Mill at Dover-Foxcroft is a 60,000 square foot historic mill complex comprised of 9 structures and a hydro dam sitting on the Piscataquis River in Maine. After sitting vacant for almost a decade, the complex was renovated and repurposed in 2015 into a mixed-use complex that now includes a high-tech business center, 22 residential apartments, space for retail shops and commercial offices, studio space for artisans, an internet café, a restaurant, boutique inn and a year-round indoor farmer’s market. The complex has become a boon to the local economy and a model for downtown revitalization across the state of Maine.

Criteria

Several key challenges existed. First, the Mill at Dover-Foxcroft was added to the National Register of Historic Places in December 2012, its 9 structures having been built between 1841 and 1944. While this designation opened up a lot of opportunities for the $11mm project to leverage historic tax credits and numerous other private and public funds, it also posed particular challenges for the developer and his team who would need to adhere to historic preservation criteria in its renovation and repurposing. Second, the developer was committed to creating a facility with zero net energy consumption utilizing the hydro dam onsite.  Third, the planned mixed-uses required that each tenant be able to control individual heating and cooling needs. Finally, consideration needed to be given to the fact that the historic mill complex is located approximately 100 miles from the Canadian border where the winter climate can be extreme.

Solution

The project’s mechanical contractor, Ranor Mechanical, recommended water source VRF technology to address all of the developer’s stated criteria. LG proposed a package of VRF products that was cost-effective not only as the best first cost, but also as a lower total operating cost over the anticipated 20 year life of the HVAC system. All of this while creating minimal disruption to the structure as dictated by the historical commission.

The LG products selected to meet the developer’s needs included LG Multi V Water Heat Recovery units, LG AC Smart premium central controller with BACnet Gateway, LG programmable thermostats and LG indoor units such as ceiling cassettes, wall mounts, high static ducted and floor standing indoor units.

The LG Multi V™ Heat Recovery VRF system with inverter-driven fan and compressor technology engages only in the zones where it’s needed — making it a highly reliable, stable solution that provides high energy efficiency. In addition to the lower refrigerant piping installation costs that LG’s hybrid heat recovery system offered, the system was able to provide simultaneous heating and cooling to flexibly match loads in all seasons while recovering heat to optimize efficiency.

Given the mill’s mixed-use, individually controlled and programmable heating and cooling for each zone, alone with remote access for alarm indication, were important selling points for the developer. Reduced utility costs and simplified property operations afforded by individual tenant billing were also appealing.

The LG Multi V™ VRF system and its duct-free design seamlessly blended into the building’s interiors. The architectural integrity of the historic mill complex and compliance with the criteria related to its placement on the National Register of Historic Places were both achieved. In recognition of this accomplishment, the architect was awarded Maine’s Historic Preservation Honor Award for Stewardship in 2015.

The LG Multi V™ VRF system and the planned 2017 hydro dam renovation will allow the developer to achieve net zero energy consumption for the mill complex. The system integrates seamlessly with the water source geothermal HVAC system designed by Ranor Mechanical. During heating months, heat is extracted from the near constant temperature below ground and used for building heating. The sheer size of the heat sink allows the extracted heat to have little effect on below ground temperature. The same applies during cooling season, building heat is rejected from the building into the ground. Water source VRF technology uses energy in the geothermal loop water and circulates it through the building using refrigerant to heat and cool. No pollution is created. Electricity is used only to operate the unit’s fan, compressor and pump. Once the hydro dam renovation is completed in 2017, the developer will utilize the hydro dam and its existing turbine to produce the electricity needed for the system, thus achieving a mill complex with net zero energy consumption.

“The energy-efficient LG Multi V™ VRF system met all criteria with flawless performance – tied in perfectly with the geothermal wells to generate big cost savings and improve energy efficiency,” said developer Jonathan Arden. “The entire project team couldn’t be more pleased with the outcome,” he added. “The mill has retained its architectural integrity and placement on the Historic Register. All of our various tenants and customers – whether they be living at the mill, or working in an office, or eating in the restaurant – are all comfortable and happy, even in the coldest winter months in Maine. And our ability to achieve net zero energy consumption once the 2017 hydro dam renovation is complete will be an additional, significant accomplishment for this project.”

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