Research Terms
Energy Consumption Energy Management Mechanical Engineering Aerospace Engineering
Industries
This open absorption cycle device for compact, low-cost, combined water heating, dehumidification, and space cooling consumes less energy and uses non-corrosive, non-toxic ionic liquid that does not crystalize. A large percentage of U.S. electricity is spent heating water and cooling, heating, and dehumidifying buildings. The average household with a standard efficiency model water heater spends more than $500 per year on water heating alone. One attempt to reduce these energy bills is the use of the absorption cycle, which can capture and repurpose low-grade heat to provide dehumidification, water heating and building cooling. However, existing absorption technology is not scalable and not feasible for residential water heating. Researchers at the University of Florida have developed a compact, high-efficiency, open absorption cycle device capable of dehumidification, water heating, and evaporative cooling. The proposed system dehumidifies the air and uses its energy for water heating. The condensed water can subsequently be given back to the dried air in an evaporative cooling process; or, when only dehumidification is desired, it can be simply drained from the system. This unit can utilize the A/C latent load for domestic water heating, resulting in significant energy savings for water heating and A/C. The system can control humidity in residential buildings, resulting in comfort and significant health benefits.
Combined dehumidification, water heating, and evaporative cooling device for energy efficient, green buildings
At the core of the system is a compact open absorption cycle in which the water vapor releases its latent heat into the absorber. The released heat is subsequently transferred into the process water that cools the absorbent. The solution is generated in the desorber where it is heated by a heating fluid. The water vapor generated in the desorber is condensed and its heat of phase change is also transferred to the process water. The system is applicable to three of the five climatic zones in the continental United States: the mixed-humid, hot-humid, and marine zones that encompass 54 percent of U.S. homes. Under typical operating conditions, the system expects to deliver 1.63 units of heat to hot water for each unit of heat supply, while reducing the A/C load by 0.63 units. The primary energy factor is about 1.14. Related to 14936
This cooling system utilizes ionic liquids to improve the coefficient of performance in an absorption refrigeration system. Cooling systems play a major role in heating, ventilating, and air conditioning (HVAC) equipment. The coefficient of performance is the ratio of heating or cooling provided to electrical energy consumed. The coefficient of performance of absorption systems has not seen a significant improvement since their introduction in the 18th century. Available absorption refrigeration systems function by evaporating the refrigerant in the desorber, which requires a large amount of energy. Researchers at the University of Florida have developed an absorption cooling system that increases the coefficient of performance by minimizing the amount of energy required during the desorption process. This is possible by using an ionic liquid and an alcohol, as the absorbent, and refrigerant that phase separates with little heating.
Increases the coefficient of performance in residential or commercial air conditioning systems
This cooling system offers competitive advantages over existing absorption refrigeration systems. The refrigerant-absorbent pairs were chosen for their ability to become immiscible with minimal heating. This immiscibility is through using an ionic liquid. When a mixture of fluid and ionic liquid is above the Lower Critical Solution Temperature (LCST), the two fluids are immiscible. Researchers at the University of Florida have developed a refrigeration cycle that facilitates the removal of a condenser. The refrigeration cycle translates to a higher coefficient of performance for the cycle.
This film-based, compact absorption refrigeration equipment repurposes heat from natural and industrial processes, creating more efficient refrigerators and air conditioners at a lower cost. Absorption refrigeration systems (ARS), also called absorption chillers, have remained relatively unchanged since their conception more than 150 years ago. The refrigerant market is only beginning to appreciate the ecofriendly aspect of absorption chillers, which repurpose industrial or solar energy that would otherwise be wasted; a technology that increases the performance of absorption cooling systems would greatly reduce global energy consumption and carbon emission. Also, existing absorption chillers with cooling capacities of 10-15 kW generally rely on shell and tube absorbers that weigh 880 pounds or more, making them too large and unwieldy for many buildings. Researchers at the University of Florida have developed an inexpensive absorption refrigeration system that is more compact, uses fewer components and performs better than existing technologies. Furthermore, these inexpensive ARSs would significantly improve the economics for combined heating, ventilating, and air conditioning (HVAC).
Absorption cooling technology that employs ultra-thin liquid film for less expensive, more efficient refrigerant and HVAC technology
This technology utilizes a porous hydrophobic membrane to improve existing absorption refrigeration technologies via the enhancement of the heat and mass transport processes involved within the system. The membrane constricts an ultra-thin liquid film (UTF), measuring 250 micrometers or less in thickness, against a cooling surface, which allows the refrigerant solution to be absorbed or desorbed through the membrane. The UTF also leads to the replacement of large shell and tube heat exchangers with small flat panel heat exchangers, thereby eliminating the entire spray nozzle system, along with associated pumps and controls. This modification is expected to make absorbent refrigeration systems require less maintenance due to the lower air penetration, less metal surface available for corrosion, and absence of spray nozzles.
Continuous operation of this electrokinetic dewatering system removes water from phosphatic clay suspensions, thereby achieving clay cake solid contents approaching 25 percent more rapidly than other methods. In Central Florida, the quantity of clay settling ponds covers more than 150 square miles, taking up approximately 40 percent of the phosphate mining land mass. Drying these clay settling ponds requires decades, and even then the clay remains too soft to build upon. Both the need to reduce the land area required for clay suspension storage and water usage in the mining operations has spurred the search for enhancing solids-liquid separation. Researchers at the University of Florida have developed a method that applies an electric field to slurries, thereby greatly enhancing the removal of water from the phosphatic clay. This process speeds up the separation of water and clay solids without the use of chemicals. This important attribute will allow potential future technologies the ability to more effectively recover the residual phosphate entrained in the clay matrix.
An electrokinetic dewatering system for extracting water from phosphatic clay suspensions more quickly than traditional gravity settling alone
The electrokinetic dewatering system includes a continuous slurry influent flow, a region for cake formation and cake dewatering, electrodes, and conveyor belts. Subjected to a uniform electric field, the dispersed particles in the influent migrate toward the conveying belt, where they form a layer of thickened clay or cake before being transferred to the cake dewatering zone, where water is further removed via electro-osmosis. The cake continues to thicken to a solids content of more than 25 weight percent and can then be collected for further drying and/or disposal. The separated water can be clarified and recycled to the beneficiation plant.
This hafnium oxide ferroelectric thin film increases ferroelectricity and thermal retention for manufacturing ferroelectric random-access memory (FeRAM). Ferroelectric random-access memory (FeRAM) is a promising emerging technology. It displays significantly lower operation voltage, read/write times, and higher endurance than flash memory. However, current FeRAM technologies suffer from poor scalability and difficulty integrating into the complementary metal-oxide semiconductor (CMOS) process, an instrumental component of modern wireless communications. Ferroelectric hafnium oxide is a new and growing field offering a solution.
Hafnium oxide-based ferroelectric thin films have been explored over the last decade since discovering silicon-doped hafnium oxide could produce a hysteresis and remanent polarization. In varying the silicone doping, it results in an array of films from ferroelectric to anti-ferroelectric. Ferroelectric hafnium is highly CMOS compatible, with its ultra-thin nature providing excellent scalability for a wide range of applications.
Researchers at the University of Florida have developed a hafnium oxide ferroelectric thin film through in situ hydrogen plasma treatment. It increases the efficacy of ferroelectric film production and ensures higher ferroelectricity and thermal retention.
Hafnium oxide ferroelectric thin films for manufacturing ferroelectric random-access memory (FeRAM), increasing ferroelectricity and thermal retention
Hafnium oxide-based ferroelectric thin films have expanded capabilities for complementary metal-oxide semiconductor (CMOS) applications. Applying oxygen (O2) and the sequential O2, hydrogen (H2) plasma oxidation controls the behavior of the resulting films from anti-ferroelectric to ferroelectric. For the sequential O2, H2 plasma films, the application of the O2 plasma occurs after the precursor pulse, followed by the H2 plasma. Using O2 and sequential O2, H2 plasma during the atomic layer depositions (ALD) offers significant tuning of the film properties from anti-ferroelectric to ferroelectric. It partially reduces the previously deposited oxide, generating oxygen vaccines and enhancing the orthorhombic phase. Adding hydrogen plasma during the atomic layer deposition improves the remanent polarization and thermal retention of the resulting ferroelectric films.
