China’s meteoric rise has had profound impacts on its economy, people, and environment. Navigant Research has examined the consequences this growth has on energy used by buildings and cities. As the country of 1.3 billion becomes more prosperous, the next transformation occurring is in cold storage. In a recent article, The New York Times Magazine delved into the adoption of refrigeration in China. On the consumer level, China’s domestic refrigerator ownership has grown from just 7 % in 1995 to 95% in 2007. As a result, the cold chain (the temperature-controlled storage and distribution infrastructure) is growing as well.
The United States, which leads the world in cold storage, currently has about 3 times the cold storage per capita as China does. In China, less than one-quarter of meat and 5% of fruits and vegetables travel through a cold chain, compared to about 70% of U.S. food. As China’s living standards rise, refrigeration and energy use are set to explode. Currently, cooling accounts for only about 15% of global electricity consumption.
The threat associated with increased living standards is not isolated to China. An estimated 40% of fruits and vegetables in India are lost to spoilage as a result of poor infrastructure. Although the Indian economy has not performed as robustly as China’s, there is hope that growth will pick up shortly. However, with that hope comes the risk of unsustainable energy consumption on a staggering scale, as India and China combined account for more than one-third of the world’s population. As such, vast advances in the energy efficiency of refrigeration are needed.
Birth of the Cool
Refrigeration, like air conditioning, relies on the vapor compression cycle. The vapor of a refrigerant is compressed to the point where it is superheated and then travels through a condenser where heat is rejected from the refrigerant vapor and it is condensed into a liquid. Next, the liquid goes through a throttle valve where it evaporates into a low-temperature, low-pressure mixture of liquid and vapor. Lastly, this mixture travels through an evaporator that absorbs heat from the space being refrigerated and evaporates the mixture so that it can be compressed and the cycle can start again.
Incremental improvements have been made in the efficiency of refrigeration, but there is a physical limit to how efficient the vapor compression refrigeration cycle can be. It may be time to rethink the fundamentals of refrigeration. The U.S. Department of Energy, for instance, has been investigating the use of non-vapor compression technology. But the answer may not be cooling at all. Cooling is a means to an end; it is an effective method of inhibiting microbial growth. But it is not the only method to do so. Fenugreen FreshPaper uses naturally occurring antimicrobials to keep fruits and vegetables fresher longer – with near-zero energy use.