Tapping into Nature: Thermoregulation
Looking to biology for heat regulation inspiration.
This is an excerpt from the Tapping into Nature report by Terrapin Bright Green.
Introducing, removing or excluding thermal energy is required for many products and systems such as adding or ventilating heat from buildings, manufacturing consumer products and operating industrial machinery.
How these flows and fluctuations of heat are managed often determines the efficiency of a design, and thermoregulation can be costly to manufacturers and consumers. Many organisms have developed replicable, low-energy strategies to maintain constant body temperatures despite temperature fluctuations in their environment, while others have developed methods to function despite extreme temperatures.
The surface area to volume ratio of an organism is calibrated to its habitat. Plants and animals in hot climates typically have large surface areas relative to their volume, while cold climates feature organisms with relatively small surface areas. In addition, organisms contain branching webs of veins and other fluid-containing channels to exchange heat with their surroundings.
These two strategies suggest ways of tailoring convective heat transfer in buildings, manufacturing processes and advanced machinery. Harbec is incorporating internal cooling channels in their injection molds, mimicking vascular systems to remove thermal energy more effectively.
Plants, animals and microorganisms survive freezing temperatures using a range of remarkable strategies. Antifreeze molecules found in organisms such as arctic fish, beetles, yeast and bacteria inhibit ice crystal growth by binding to ice crystals before they expand and aggregate. These molecules are of great interest to companies such as fuel cell manufacturers that want to prevent liquid fuel from freezing and food manufactures such as Unilever, which uses an antifreeze protein to create creamier ice cream.
To survive elevated temperatures and extreme dryness, certain organisms chemically stabilize their proteins and tissues. Microorganisms that thrive at high temperatures feature enzymes that function up to 110 degrees Celsius (230 degrees Fahrenheit). These enzymes were instrumental in the development of the revolutionary genetic analysis technique known as PCR.
Organisms, such as the tardigrade, are capable of withstanding not only high temperatures but also desiccation. This inspired the development of dry vaccines and biological preservation technologies commercialized by Nova Laboratories and Biomatrica. Cold storage is unnecessary due to the products’ ability to maintain the integrity of thermally sensitive chemical compounds, reducing shipping and storage costs.
HydRIS dry vaccines
Nova Laboratories mimicked the extreme desiccation abilities of certain organisms to develop "dry" vaccines. Standard vaccines contain biological material that must be refrigerated, requiring energy intensive supply chains (known as "cold chains") that keep the vaccines at low temperatures from manufacture to administration.
Nova’s dry vaccine platform technology (known as HydRIS) preserves the vaccine material in a dry, sugar glass matrix for transport. The vaccines are rehydrated just before administration to the patient. This platform technology creates chemically and physically stable vaccines while withstanding temperatures of 0-50 C (32-122 F) without compromising potency, saving on energy and transportation costs and allowing vaccines to be transported to remote areas.
Unilever ice cream
Ice cream — a $60 billion market in 2013 — requires considerable energy throughout its refrigerated supply chain. The texture of ice cream is dictated by the small size and regularity of its ice crystals. If ice cream thaws and refreezes, ice crystals grow and accumulate, decreasing the quality of the product. In developing economies, however, refrigeration is not always available.
Recently, product manufacturer Unilever introduced an ice structuring protein first identified in arctic fish to prevent the growth of ice crystals. Approved by the U.S. FDA and its counterparts in the European Union and Australia, this ingredient allows ice cream products to undergo freeze-thaw cycles with minimal crystal growth, ensuring a high quality product reaches consumers even over imperfect supply chains in warm climates.
Products in development
The manufacture of injection molded plastic parts involves both the introduction of high thermal energy and its removal. Cooling fluids are used to extract the supplied heat from each part, creating an energy-intensive process.
New York-based plastics manufacturer Harbec tapped Terrapin’s network of biomimicry experts and built a multidisciplinary design and engineering team with Jiandi Wan of RIT and Abraham Stroock of Cornell University. Applying a biomimetic approach to the redesign of the metal molds, the team is looking at counter-current heat exchangers, such as human lungs, to learn how nature dissipates heat quickly and efficiently. Prototypes feature webs of cooling passages rather than the simple, straight cooling channels found in conventional molds. A biomimetic mold that cools quickly will allow Harbec to differentiate itself from competitors. Specifically, shorter cooling cycles lead to lower power consumption and increased production speed, which translates into lower costs and higher revenues for Harbec.
This is the first in a series of Tapping into Nature articles, which will appear in full here.