1. Needs Assessment

According to the size and cooling/heating needs of your building, your heat pump supplier will recommend a heat pump able to provide the proper tonnage. Prior to that, Brewster Well Drilling and your heat pump supplier will also have determined whether your geothermal system should be open or closed.

The open loop circuit consists in drilling two wells. The first one used to supply the heat pump and the second one to be used as absorption well. The water pumped from the ground is used as coolant. The open loop
system is suitable where there is access to a large amount of water, not to deep into the ground. The source must also be of high quality (low in iron, limestone and sulphur), in order to avoid a build up of deposits. Deposits could damage the pump in the long run. Note that open loop systems are mainly used for
larger projects.

The closed loop system is the system mostly used these past few years. A closed loop system circulates a heat transfer fluid (usually 25% antifreeze / 75% water) through a system of pipes inserted in the boreholes. The space between the piping and the borehole's wall is then filled with a filling material in order to allow a good temperature transfer, from the ground to the coolant (heat transfer fluid). This system is very stable and highly reliable when installed by geothermal drilling experts.

Prior to installation, one of our specialists will meet with you, on site, to discuss the borehole locations and survey the area.

2. Borehole(s) Drilling

When drilling, our experts use 6 inch wide rotary drills. On average, we need to drill 150 feet for every ton of heat/cooling required. In other words, we need to drill 300 feet deep for a building requiring two tons of heat/cooling. Depending how many feet are needed, we will decide whether to drill more than one borehole. Rarely do we need to drill more than 600 feet deep. For a location requiring 900 feet of drilling, we will usually choose to drill 2 boreholes of 450 feet each. When more than one borehole is needed, there must be a minimal distance of 15 feet between each one. In order to avoid dead soil to crumble and fill the borehole, a steel casing will be inserted and anchored approximately 6 feet into the solid rock.

3. Piping Installation (Closed Loop)

Polyethylene CSA pipes are used in order to circulate the anti-freeze solution inside the borehole. In our workshop, the pipes are fused, filled and then tested for 24 hours, in order to ensure they are well sealed. When we are satisfied there is no leak, the pipe is inserted into the borehole.

4. Borehole(s) Filling / Grouting (Closed Loop)

Once the pipe is inserted, the remaining space around the pipe is filled with a filling material. We normally use either silica sand or chlorite schist. This will guarantee a good heat exchange between the ground and the coolant.

Depending on the project, we may also choose to use a mix of silica sand, Therm-Ex bentonite and water. A high pressure injection pump will inject the mixture from the bottom to the top of each borehole (tremie type injection). This method meets CSA standards.

5. Horizontal Piping Installation

Afterwards, we install the horizontal piping. These pipes will be used to connect the borehole exit to the building. This is where your heat pump installer takes over. He will be the one connecting the pipes to the heat pump.

Brewster Well Drilling: The Right Choice For Your Geothermal Project!

Over the years, Brewster Well Drilling has carried out as many large scale projects as it has residential ones. We have the knowledge, equipment and employees to successfully conduct any of these mandates. Whether your site requires 100 boreholes, or you just want to take advantage of this technology for your family residence, Brewster Well Drilling’s reliability and professionalism is what you need! We will carry out your geothermal project successfully!