Mansion House on Martha’s Vineyard Goes Geothermal
The Mansion House has over 16,000 gallons per day of groundwater in the basement that must be pumped out. This represents a tremendous open source geothermal resource that can be used to cool the hotel.
The groundwater is pumped outside to the fluid cooler to remove heat from the geothermal building loop that circulates in the hotel. The heat pumps in all common spaces and all 50 guest rooms are connected to this geothermal building loop.
The operation of the fluid cooler, the circulators and sump pumps are controlled by a DDC (direct digital control) panel.
Because of the reduction in the cooling load experienced by the fluid cooler, several new heat pumps could be added to the Mansion House common areas. These heat pumps are integrated with the existing heat pump system using closely spaced tees on the main geothermal building loop so that the existing loop circulators are not overloaded.
The article below is from 2010:
Mansion House on Martha’s Vineyard Goes Geothermal:
A new geothermal heat pump system, run by the stored solar energy found in the abundant ground water below the Mansion House, and a sophisticated energy control system makes the hotel one of the greenest hotels in Massachusetts. Mansion House’s cooling system now uses geothermal heat pumps to remove heat from the hotel and store it deep underground for use in heating the hotel during the winter. The new energy control system carefully controls where this green heating and cooling is used to maximize energy efficiency and maintain guest comfort. All of these advances result in a marked decrease in energy usage and pollution by the hotel; limit fossil fuel use, energy waste and carbon dioxide production. These cutting-edge systems combine to make Mansion House Inn the greenest hotel on Martha’s Vineyard and one of the leading green hotels in the state and nation.
Geothermal Heating and Cooling System:
Up until recently roughly 16,000 gallons of groundwater a day ran under the Mansion House untapped, a nuisance to be pumped away instead of used as a valuable source of “stored solar energy”. The recently completed geothermal heat pump system uses this energy source for cooling the guest rooms and common spaces. The heat removed from the hotel by the heat pumps is sent to the groundwater running under the hotel. This heat energy and water is ultimately redistributed back into the water table where it is stored.
A proposed second phase to this geothermal project will expand the system to harvest this heat energy using the heat pumps. Year round, all of the hotel’s domestic hot water and pool heating will come from the “stored solar energy” in the groundwater. In addition, a planned roof top garden, irrigated by the groundwater before it returns to the water table, will supply fresh produce to Zephrus Restaurant.
A Brief History of the greening of the Mansion House
In the fall of 2007, Martha’s Vineyard-based green contractor Nelson Mechanical Design (NMD) met with Sherm Goldstein, owner of the Mansion House, to discuss energy efficiency possibilities at the hotel. Jay McMann, the hotel plant engineer, had attended a geothermal open house that NMD held. McMann, who also is the principal of a company that delivers fuel to the hotel, saw that NMD could be of benefit to the Mansion House. Putting energy conservation first, Jay overlooked the personal economic results of reducing Mansion House’s fuel bill.
In 2007 Goldstein asked NMD to do a study of the Mansion House’s energy use and to create a roadmap of how to make the hotel greener. A careful study of the heating, cooling, and hot water systems led to the development of several key projects discussed in an Energy Proposal that would make the hotel the greenest in Massachusetts – including a geothermal heating and cooling system, a comprehensive control system (DDC or direct digital control), and the use of ground water to heat the pool and domestic hot water.
RISE, Cape Light Compact, and the Mansion House Green Vision Study
In 2009, Goldstein brought RISE (administering the Cape Light Compact rebate programs) to the Mansion House to work on lighting retrofits. It became apparent that a partnership between RISE and NMD could work to make the Mansion House green vision a reality. Several projects were proposed and ultimately two were formalized and funded for installation at the Mansion House in 2010: a DDC system installation to control and monitor all guest rooms and common spaces and a geothermal ground water system to retrofit the heating and cooling system. RISE and NMD provided engineering and technical data to support the project applications and the Cape Light Compact administered their rebate funding program to pay for a significant percentage of the work.
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