An analysis to identify an optimal location for heat transfer to remove a natural heat island – a case study

The temperature of the Central Valley of California is relatively higher than the surrounding area, making it ‘natural heat island.’ The Central Valley could be benefitted in different sectors such as energy consumption, public health, agriculture, wind energy, precipitation, and economic growth if the temperature could be reduced even by a few degrees. The objective of this study is classified in two categories. First, to assess the benefit models for these sectors due to reduction of the temperature. Second, to locate the best possible locations to cleave off the top of mountains on the Coastal Mountain Range that are blocking relatively cooler wind from the coastal area to enter the Valley. Benefit models in all of the sectors show potential positive impact due to temperature reduction on Valley’s current status of these sectors. Cleaving off the mountain produces new area, which can be used for wind energy generation, agriculture, and other purposes. Existing literature showing the impact of temperature on these sectors has been collected to study the potential benefits of temperature reduction in the Valley. Methodology to locate the possible locations on Coastal Range involves collection of weather data (such as wind speed and velocity), atmospheric pressure data, and geospatial data. Weather data from California Irrigation Management System (CIMIS), atmospheric pressure data from National Oceanic and Atmospheric Administration (NOAA), and geospatial data from United States Geological Survey’s (USGS’s) National Elevation Dataset (NED) are used for the analysis. Using the weather data, wind flow maps in study area have been created for different times of a day (i.e., 12 am, 6 am, 12 pm and 6 pm). Such maps show westerly winds prevailing for most of the months. Autodesk Flow Design was used to create a simple wind flow model to simulate the wind flow pattern over different zones of the study area. The simple wind flow model gives insight of the wind pattern over the study area under different conditions of elevation and wind velocity. Pressure gradient, elevation, and slope are the major criteria that govern suitability of the locations. Using a brute force method, an optimization model to minimize the sum of length of all locations was solved for different pressure gradients, elevations, and slope criteria to find the best possible locations. The total affected area for the locations with elevation greater than 5000 ft., slope smaller than 20%, and pressure gradient 0.0008 to 0.001 Pa/Km was about 77.5 square miles. The optimal sites concentrate mostly in the southern region (i.e., the Sierra Madre Mountains west of Bakersfield), central region close to Monterey, and the Coastal Range west of Fresno at similar latitude and on the northern region on the mountains near Santa Clara.