NMD Lab Geothermal System

pix 2 Lab DDC inside

The residence of Brian K. Nelson and family houses a very unique mechanical room. For years, the basement of the Nelson Residence has been used as the heating, cooling, and domestic hot water plant for their home. But it has also been used as a testing grounds for new heating and cooling technologies and control systems.

NGT Loop 2 M22 Vapor w B 112905

Currently, an eight ton horizontal geothermal DX ground to water system provides all of the heating, cooling, and domestic hot water pre-heat for the Nelson family.
(these are 1/4″ copper tubes buried 6′ below grade)




(this is the manifold used to collect refrigerant from the 1/4″ copper tubes buried 6′ below grade.)




pix p Lab Heat pumps and display

Two four ton heat pumps take turns raising the temperature of the heating tank or lowering the temperature of the cooling tank to provide warm air heat and air conditioning.



pix o Lab Heat pump circulators

(these circulators send water through the two heat pumps and to and from the various storage tanks)





pix m Lab Hot loop circ Chilled loop circ Chilled tank Hot tank

(storage tanks for chilled water on the left and hot water on the right)






This hot or chilled water is sent to two air handlers and run through oversized hydronic coils.





(the oversized custom coils are designed to work with very low water temperatures to permit maximum use of solar hot water for space heating)





pix 9 Air handler circulators and hot and chilled loops left

(these circulators and motorized valves send either chilled or hot water to the various air handlers from the storage tanks)






This system preheats the domestic hot water in conjunction with an AET solar hot water panel system. As a backup, a Noritz tankless hot water system boosts the domestic hot water when needed.

(this is the storage tank for domestic hot water)





(these are the circulators for the solar collectors on the roof)





pix q Lab display and pressure gauges

A Direct Digital Control System, or DDC, controls every aspect of the homes heating, cooling, and solar hot water systems. A flat screen display shows tons of carbon dioxide and money saved, as well as current function of the system. Both the DDC and traditional guages and meters display ground, water, and air temperatures throughout the system as well as water and air pressures. This allows us to measure the performance of the system and compare real world data with our software projections.


pix 5 Lab Circ Controls Diverting Valve Controls


(these meters indicate voltage sent to all variable speed circulators and blowers)









Our goal is to be Martha’s Vineyard’s premier plumbing and HVAC shop – we appreciate the opportunity to show you some of our work.