The Canadian Prairies experience long

cold winters

making indoor farming with controlled environments an attractive solution for year-round vegetable production. Repurposing unused underground mine tunnels to house plant factories shields them from the elements. This study aims to conduct thermal simulations by integrating passive ventilation (PV) and heat recovery techniques into the heating

ventilation

and air conditioning (HVAC) system

forming a PV-HVAC system

to reduce energy consumption and assess the economic feasibility of underground plant factories (UGPF). Utilizing OpenStudio software for thermal simulation

the results demonstrate that the PV-HVAC system reduces HVAC electricity consumption by 74.5% compared to the base case (chiller cooling without heat recovery) and achieves a coefficient of performance (COP) of 12.05. While the PV-HVAC system significantly decreases chiller and boiler energy consumption

there is a slight increase in fan electricity consumption and a humidifier is needed to maintain humidity setpoints. The economic feasibility study reveals an internal rate of return

profitability index

net present value

and payback period of 13.88%

1.28

$608

460

and 6.7 years

respectively

indicating the project's feasibility.