BASICS OF HOW GEOTHERMAL HVAC WORKS

There are a few geothermal systems in urban areas, especially New York City! Closed-loop ground source systems are typical installations for urban environments and are good considerations for new construction.

Bedrock actually has great thermal conductivity properties and certain drilling equipment is capable of drilling in bedrock to install ground loops.

Once the ground loops are installed and sealed, there is no maintenance involved. Operations are related to water source heat pumps and piping, but generally do not require further specialized knowledge. Geothermal systems will offer less O&M and have longer useful life than other systems since all equipment is underground and inside the buildings, protecting the system components to everyday and extreme weather events.

Brightcore’s fleet of rigs includes a custom mini rig, which is specifically designed for drilling indoors. It is smaller than conventional equipment with 10 feet head clearance and 9 feet long, allowing it to fit in small spaces with low overhead clearance, while minimizing the risk of damaging surrounding buildings or structures.

Closed loop geothermal systems circulate a mixture of water and anti-freeze in the ground loops to the heat pumps. Heat pumps use refrigerants for heat conversion, but geothermal systems minimize and centralize the refrigerants to the heat pump itself. The refrigerant isolated in one geothermal system component makes it simple to dispose of and replace at the end of the heat pump life (up to 25 years!)

While it is true that conventional air-down-the-hole (ADTH) drilling techniques typically deviate from their expected drill path by up to 10%, Brightcore’s proprietary water-down-the-hole (WDTH) drill rig only deviates from its drill path by about 1%. In a densely populated area like New York city, this higher degree of precision allows for more precise drilling in ‘close quarters’ near critical underground infrastructure like NYC water tunnels as well as in and around landmarked buildings.

Manufacturer warranties range from 50 to 65 years, but the ground loops themselves can last more than 100 years with the durable HDPE piping and limited exposure to weathering.

Combining ground source and air source heat pumps can produce the most efficient solution by leveraging each technologies’ efficiencies. For heating and cooling in shoulder seasons with milder temperatures, ASHP can operate at its highest efficiencies. On the other hand, geothermal can supply a majority of demand during peak hours and temperatures with the lowest electricity use. Together, each system can work together to meet building demands in the most efficient way.

Although drilling in bedrock with traditional equipment, such as an air hammer and mud rotary, is not impossible, it can be challenging and messy. This would be applicable to sites that have lots of space and wouldn’t interrupt surroundings. On the other hand, the Water Down Hole drill is specialized to drill in bedrock without major debris or disruption. For this reason, the five boroughs, and Manhattan especially, are ideal drilling locations for ground source heat pump installations.

NYC’s iconic skyline wouldn’t be possible without bedrock as its foundation. Bedrock can also become the pillar for renewable heating and cooling by using a specialized water-down-the-hole (WDTH) drilling technology capable of accurately drilling in rock. The combination of types of bedrock and its ideal thermal qualities, NYC is a great candidate for ground source heat pumps.

For ground source heat pumps to provide enough heating and cooling for large commercial or multifamily buildings, it’s common to drill 500 to 800 feet. However, this drilling occurs in the crust of the Earth and not the mantel where magma circulates 225 miles below!

Instead, closed loop HPDE pipes circulate water and anti-freeze in the ground to transfer heat for building geothermal heating and cooling applications.

Drilling operations are not large enough to cause geological impacts as intense as earthquakes. Geothermal installations should be considerate of any existing sensitive geologic conditions such as existing fault lines, but are not able to create extensive fractures.

Conventional drilling techniques require at least 20’ of spacing between boreholes, if not more, Brightcore’s UrbanGeo inclined boreholes only require ~ 5’ between each borehole.