Spacing of Wells for Heat Pumps

Abstract

An approach to selecting the spacing of wells for ground‐water heat pumps is developed. Breakthrough times for different well spacings are tabulated taking into account typical ground‐water velocities, well flow rates, and flow directions. Typical sizes of residential lots are given. Tables are prepared to show ground‐water temperatures at the producing well for different times after breakthrough. Adverse conditions to be expected during operation of the heat pump are described and some remedial measures are suggested. In most aquifers a spacing of 50 ft–75 ft (15.24 m–22.86 m) is satisfactory between the production and injection wells. The space between neighboring heat pump systems should be larger than the spacing between wells. In densely populated locations the available area may not provide for adequate spacing of wells. In such cases, the anisotropy of most aquifers can be utilized to good advantage by pumping out from the top of the aquifer and reinjecting at the bottom of the same well.