Filed Under Air Conditioning

Cooling the Desert

The Secret Infrastructure of Arizona State University

Searing heat scorches Tempe, Arizona and the Sonoran Desert from May through September and the only beacon of relief from the oppressive heat is air conditioning. With a tap of the thermostat…presto, the magic of chilled air wafts from our vents. Without the emergence of air conditioning, the massive migrations that led to the development of metropolitan Phoenix probably not have happened. However, the process through which air is cooled—not to mention its history--is a mystery for most people. If the Southwest as it is today would not exist without AC, neither would Arizona State University. Thus, sharing the history of air conditioning at ASU, and its evolution over the last century, tells us much about the emergence of the University and the region.

Already, early 20th century, the Tempe Normal School of Arizona (ASU) selling students on the cool comfort of the dormitories played a role in the University’s published materials. For example, the June 1916 Bulletin of the Tempe Normal School of Arizona noted that sleeping porches were integrated in dormitories to keep students cool while they slept . They were described as, “…a wing, open on three sides to the air and two stories in height. It is screened all round, fitted with storm curtains, and affords room for all occupants of the building, who are thus enabled to sleep comfortably in the open air the entire year.” The sleeping porches—perhaps coupled with oscillating fans--would have been necessary for a comfortable night of sleep. For example, on June 15, 1916, about the time when the Bulletin of the Tempe Normal School of Arizona was published, temperatures soared to a devastating 111° Fahrenheit. Later that autumn, in August, the average monthly high was over 100 degrees and the average low was about 73 degree--both substantially cooler than is typical in summer. Advertising the comfort of sleeping porches to prospective students would have reassured them that the desert was habitable in summer.

From the humble beginnings of sleeping porches to icy breeze from AC vents today, climate control has changed dramatically and become ubiquitous, even in cool northern climates. Evaporative cooling, also known as swamp coolers, represented a first big transition in 1936. These coolers could reduce the temperature anywhere from twenty to thirty degrees, especially before monsoon season, working best in the hot, dry climates of Tempe. By blowing air through damp pads with an electric fan, these swamp coolers provided a welcome relief from the blistering heat. Unfortunately, swamp coolers introduced humidity into the air, which caused an uncomfortable stickiness at times. Even so, as many as 90 percent of Phoenix-area homes had swamp coolers by the 1950s—the same decade in which electric window air-condition units began to be commonly used. In fact, across the United States more than one million of these units were sold in 1953 alone. Unlike swamp coolers, they dehumidified the air and alleviated the stickiness that swamp coolers introduced. Just as television spread rapidly in the 1950s, so too did air conditioning. These de-humidifying air conditioners--so prevalent today—became increasingly common in hot desert climates; central air conditioning was included in much new construction by the end of the 1960s. In the 21st century, more than 80 percent of all American homes have some form of air conditioning.

Keeping up with the cooling needs of a growing student population at ASU proved challenging—one met through an elaborate infrastructure. Ten to fifteen feet under the Tempe campus is a maze of tunnels that chilled air must travel to reach the buildings and classrooms at ASU. Walled in concrete, these tunnels are approximately 5 miles in length and stretch from Apache Boulevard to Sun Devil Stadium . One of the Facilities Management Directors at ASU explains that most of the tunnel system have been here as long as the campus has, but more tunnels have been added to service the needs of the campus . Some tunnels measure eight feet high and seven feet wide and were built at the same time the malls and walkways at ASU were built. Industrial-grade pipes funnel the cold air through a subterranean maze of tunnels and return the warmer air to ASU’s Central Plant.

The Central Plant at ASU provides the full spectrum of climate control for the entire Tempe campus. There have been several Central Plants here at ASU; the first was built in 1906 as a heating plant for the cost of $19,000, but was demolished and salvaged to build a second heating plant in 1917 at a cost of $56,000. A third plant was built in 1937, but it would not be until 1959 that a refrigeration system was introduced to campus. At a total cost of $1,217,870.70, Lowry & Sorenson engineered and constructed the refrigeration system as an add-on to the third Central Plant. Electricity rates skyrocketed with the emergence of AC and with a large campus to service, cost of electricity was a concern.

By the 1980s, as the University’s energy and cooling needs expanded, David Scheatzle, an alumnus and Professor Emeritus of ASU, proposed geothermal storage as a means to save ASU money on spiking energy costs. His plan involved cooling water used for air conditioning at night when electricity costs were significantly lower, store this chilled water in underground tanks, and distribute during the day to keep the campus cooled. He received a $10,000 grant to research his proposal of placing thermal tanks underground and worked with Bridgers & Paxton, a company in Albuquerque New Mexico to bring this plan to fruition. The Sun Devil Fitness Complex (SDFC) Intramural Fields is a beautiful lush expanse of green grass, but buried deep below are immense thermal tanks used to store cold water to bring AC throughout the Tempe campus.

AC is a standard feature of the southwest and everyone moves in an air-conditioned bubble, from home to car, car to class or work, and back again. Peruse the ASU catalog and notice there is no mention of air conditioning anywhere. Living in the wretched triple-digit heat of Arizona without AC is unimaginable, until the AC malfunctions. Then people get a little taste of how early Arizonans felt like without the comfort of air conditioning to ease the stifling heat. Let us appreciate the advances of air conditioning technology and count our blessings that the time of sleeping porches and swamp coolers have paved the way for the AC of today.


University Drive Pedestrian Overpass
University Drive Pedestrian Overpass The overpass provides a crossing over University Drive; it houses lines for steam, chilled water, and emergency power for the north campus, as well as telecommunication lines. Source: Arizona State University Archives, Media Relations Photographs, ACC #2000-02200. Creator: Arizona State University Date: 1986
ASU Central Plant
ASU Central Plant The Central Plant of ASU that shows the majestic view of the inner workings of the climate control at ASU. Source: Arizona Archives Online, Arizona State University Photography Collection: Buildings and Grounds 1886-1984, UP UPC ASUB C36 Creator: Arizona State University Date: 1950-1980
Matthew's Hall
Matthew's Hall Taken in 1924, this is a dormitory that has the sleeping porch extension. Source: University Archives Photographs, Tempe Campus 1924-25 Creator: Arizona State University Libraries Date: 1924
Sun Devil Energy Center at Arizona State University
Sun Devil Energy Center at Arizona State University The Energy Center under construction during 2006. Rather than have the climate control visible, during construction they camouflaged the building so that it would look similar to the rest of the Tempe campus. Source: Machado Silvettie, Portfolio, ASU Creator: Machado Silvetti Date: 2006
Inside Sleeping Dorms
Inside Sleeping Dorms Gertrude Perkins and a friend posing in the sleeping porch in the girls dormitory likely at East Hall which is known as today's Hayden Library. Source: Gertrude Reed Perkins Photographs, University Archives, ASU Library. Creator: Gertrude Reed Perkins Date: c.1927
First Heating Plant
First Heating Plant Building document that provides details on the first Heating Plant at the Tempe Normal School (ASU) that provides the cost and construction. Source: Documentary History, Part X Buildings, Volume 10, Part 10 Creator: Arizona State University
ASU Insight Publication
ASU Insight Publication David Scheatzle is warded a $10,000 grant for his thermal energy storage study as a means of reducing peak electrical demand. Source: ASU Insight, Official Faculty/Staff Publication, Volume 7, Number 5 Creator: Arizona State University Date: August 4, 1986
SDFC Intramural Field
SDFC Intramural Field Present day SDFC Intramural Field where softball or baseball games are played, but buried under the field are the thermal tanks used to cool the University. Source: Arizona State Press Creator: The State Press Date: September 8, 2010



Mandy Hall, “Cooling the Desert,” Salt River Stories, accessed May 23, 2024,