ATES – Project Haystack




The ates tag is used to model an aquifer thermal energy storage system. ATES systems are designed to use underground water to store thermal energy and deliver heating and cooling to a building in a very energy efficient way, often in combination with a heat pump. The ATES consists of all parts of the system that interact directly with the underground water up to and including the heat exchanger that transfers energy into the building hot water plant.

An ATES always has one or more well equips. Wells facilitate the thermal energy exchange with the ground warm and cold water sources. A well can be either a closed system that transports water through pipes in the ground, or it can be an open system that pumps up and returns ground water.

In most cases, there is also a flowInverter equip to change direction of the flow between the different well equips.

There are always one or more heatExchangers to transfer energy from the ATES into the hot and/or cold water plant of the building. In some cases there are multiple buildings connected to a single ATES system with one or more heat exchangers per building.


An ATES must be tagged using the ates and equip marker tags. In addition, it must define one of the atesDesign choices.


Wells should always be marked as well and equip. They are modeled as the children of an ates equip.

In an ATES, each well should tagged with exactly one of the following markers:

  • warm: well stores heating energy
  • cool: well stores cooling energy
  • infiltration: water is pumped into ground water layer
  • extraction: ground water is pumped out

Extraction and infiltration are used in the process of extracting water from a ground water source, typically taking it through piping and a heat exchanger using a pump, and infiltrating the same water back into the ground at another location or another depth (another ground water layer).