Low Cost Self-Sustaining Year-Round High Tunnel Temperature Control

Project Overview

Project Type: Farmer
Funds awarded in 2020: $14,781.00
Projected End Date: 09/30/2021
Grant Recipient: T. L. Fruits and Vegetables LLC
Region: Northeast
State: West Virginia
Project Leader:
Tommye Rafes
T. L. Fruits and Vegetables LLC


Not commodity specific


  • Energy: geothermal, solar energy, wind power

    Proposal summary:

    High tunnel temperature control is critical to year-round crop growth; yet can be both challenging and expensive. The objective of this study is to develop an effective low cost self-sustaining temperature moderation system for large (defined as 30ft by 96ft) high tunnels utilizing a geothermal network, powered by a configuration of solar panels, wind turbine and batteries to energize fans that will circulate moderating air into the high tunnel from geothermal piping. We plan to demonstrate that this system can support year-round plant growth including during extreme hot and cold temperatures.

    The geothermal high tunnel will have four high speed fans powered by ten solar panels, a wind turbine and six batteries with component adjustments made if needed. Temperature data inside the geothermal high tunnel and a second “control” high tunnel will be collected during designated summer and winter months in 2020 and 2021 when the temperature in a control non-geothermal second high tunnel exceeds 85 degrees or is below 40 degrees. Data will also be documented on estimated cost of materials and operation for three possible options for farmers who wish to grow year-round crops: 1. Cost of propane/natural gas heating systems with fuel (no cooling with this option), 2. Cost of geothermal network that is not self-sustaining and 3. Cost of a self-sustaining geothermal/solar/wind energy system. Upon completion of testing, an analysis of the temperature moderation and relative cost data will be made.

    The project will be publicized through presentations, farm visits, new releases and internet postings.

    Project objectives from proposal:

    This project seeks to discover if a geothermal high tunnel powered by self-sustaining solar/wind energy is a viable option for farmers wanting to farm year-round in climates susceptible to extreme hot and cold temperatures. In studying this objective, this project seeks to determine the following:

    1. Whether a self-sustaining geothermal solar/wind energy system can sufficiently heat a high tunnel during temperatures below 40 degrees for several days without a supplemental heat source such as natural gas.
    2. Whether a self-sustaining geothermal solar/wind energy system can sufficiently cool a high tunnel during temperatures above 85 degrees and if so, can it do so for extended periods during the hot summer months as in West Virginia.
    3. The optimum design configuration for such a system in terms of solar, wind turbine and battery interface.
    4. The relative materials and operating costs of traditional geothermal, self-sustaining geothermal, and natural gas/propane systems both in start-up and annual operating costs.
    5. Whether the sides of a high tunnel should be open or closed when cooling the high tunnel using geothermal energy.
    6. The optimum fan air velocities (CFM) in the underground pipes to effectively transmit and moderate the heating and cooling in a large high tunnel.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.