JAUE2017-072: Applicability of a Geothermal Ventilation System to Regions With Large Diurnal Temperature Variations

Abstract

In this paper, we studied San Diego, which is located in California, known as the state with the highest degree 
of energy-saving in the United States. The San Diego climate, which is characterized by large differences between 
day- and night-time temperatures, is considerably different from that of Japan. The heat capacities of soil and
cobblestone layers adopted in a geothermal ventilation system (GVS) couuld help reduce this large diurnal 
temperature variation in San Diego. Measurements show that the largest difference between day- and night-time
temperatures was about 25°C, whereas the fluctuation of the outlet temperature of a ground heat exchanger was 
maintained within about 5°C because of the high heat capacity of the soil. In addition, the temperature of supplied 
air was maintained owing to the high heat capacity of the cobblestone layer under the floor. The results of 
numerical computation of outlet temperatures of a ground heat exchanger are consistent with the measured results. 
Heat capacities of the soil and cobblestone layers in a GVS are verified as effective at moderating the large diurnal 
temperature variation in San Diego