Submitted by James O’Brien, Greenwich
Letter To The Editor
It does not make common sense much less economic and health sense why the Central Middle School Building Committee (CMSBC) is proposing a traditional gas fired boiler system with air sourced heat pumps (A/C) as opposed to a Geothermal Water Source Heat Pump System (GSHP)* for the school’s heating, ventilating and air conditioning (HVAC) systems.
A GSHP system costs much less in all respects (start-up, annual energy use, maintenance and replacement expenses) compared to the traditional gas fired system.
The globally noted energy analysis firm, Thornton Tomasetti (TT), was hired by the Architect and paid handsomely, I’m sure, to write an energy analysis report that compared the costs of three proposed HVAC systems by the Architect. TT recommended the GSHP system with solar cells. The Construction Management Company hired by the CMSBC, Turner Construction (a great decision), also recommended the GSHP.
They both did so due to the following cost savings: First, approximately 40% of incentives for using GSHP from the Inflation Reduction Act (IRA); Second, a potential Energize CT square foot incentive for further lowering the initial cost; Third, the GSHP option would be significantly more energy efficient, and thus less expensive to run. Finally, the eventual replacement cost of the geothermal option is much lower than the alternatives.
According to TT the initial purchase net cost of the GSHP system is $5.5M with a Power Purchase Agreement (PPA)* and solar included. The initial cost of the traditional gas fired boiler and air source heat pump system is $12.6M. The report states that the Energy Use Intensiy or the Coefficient of Performance (COP – Output/Input of energy) for the GSHP with PPA and soler cells is 4.35. The COP for the approved all gas system is .96. In other words the energy efficiency and therefore cost to run the all gas system is more than four times more costly to heat and cool CMS then the Geothermal system.
Their report further states that the future replacement costs in today’s money for the GSHP system is $17.4M while the chosen all gas system replacement cost is $26.2M.
There is quite a bit of misinformation about previous experience with the GSHP system at Hamilton Ave School and a solar system at Glenville School. The documented facts are that those failures were respectively caused by poor operation and lack of maintenance. These will not be an issue with the added team member Turner Construction and a PPA. Another false objection, a GSHP system will extend the finish schedule, with innovative drilling techniques now utilized by the industry it will not.
The P&Z Commission and the RTM should look skeptically upon the CMSBC’s MI application if it continues to ignore the cost effective and energy efficient GSHP.
These systems are widespread nationally as well as installed in many of the larger residences here in Greenwich.
* Geothermal water source heat pump system – is an underground heat collector and storer of heat – it uses the earth as a heat source and sink (thermal or heat storage), using a series of connected pipes buried in the ground near a building with water as the transfer agent of the heat. The loop of pipes can be buried either vertically or horizontally. It collects heat from the ground and transfers it into the building during winter. For air conditioning it works in reverse and transfers heat from the building into the ground.
* Power Purchase Agreement (PPA) – is an arrangement in which a third-party developer installs, owns, and operates an energy system on a customer’s property. An agreement for the cost of electricity produced on their property is made between the two parties. They also can teach the owner how to run the system for an eventually take over.