Capillary mat heat exchangers are increasingly used in transportation energy tunnels due to their large heat transfer area

uniform temperature

etc. Thermal energy tunnel

as a new type of energy tunnel

is different from transportation energy tunnels due to its internal heat source. To examine the feasibility of applying capillary mat heat exchangers in thermal energy tunnels

heat transfer performances of them are experimentally investigated in a thermal energy tunnel using 1:1 intermittent operating mode. The results show that the higher the initial air temperature (T0) in the tunnel is

the greater is the heat transfer rate per mat area (q). As the T0 increases by 10°C

the q increases by 45.9%. The q increases with the increase of circulating water velocity (u)

presenting an exponential change. When u increases up to 0.1m/s

the q tends to be stable. The lower the inlet temperature of circulating water (tin) is

the greater is the q. During the heat transfer process

the q reaches 143.09W/m2~187.22W/m2

which is much higher than that of transportation energy tunnels. The results can provide a basis for the design and application of capillary mat heat exchangers in energy tunnels with internal heat sources.