Kyle Gluesenkamp

A Hybrid Absorption Cycle for Water Heating, Dehumidification, and Evaporative Cooling

In this study, development of a novel system for combined water heating, dehumidification, and space cooling is discussed. The system absorbs water vapor from an air stream into an absorbent. The latent heat of absorption, released into the absorbent, is transferred into the process water that cools the absorbent. The solution is regenerated 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 condensed water is then used in an evaporative cooling process to cool the dehumidified air exiting the absorber. Essentially, this open-absorption cycle collects space sensible heat and transfers it to hot water. Another novel feature of the cycle is recovery of the heat energy from the solution exiting the desorber by heat exchange with process water rather than with the solution exiting the absorber. This approach has enabled heating the process water from an inlet temperature of 15°C to 57°C (conforming to the required DOE building hot water standard) and compact fabrication of the absorber, solution heat exchanger, and desorber in plate and frame configuration. The system under development currently has a water heating capacity of 1.5 kW and a thermal coefficient of performance (COP) of 1.45.© 2015 ASME

Transient Thermofluids Analysis of a Ground-Level Integrated Diverse Energy Storage (GLIDES) System

In this work, a novel Ground-Level Integrated Diverse Energy Storage (GLIDES) system which can store energy via input of electricity or heat and deliver dispatchable electricity is presented [1]. The proposed system is low-cost and hybridizes compressed air and pumped-storage approaches that will allow for the off-peak storage of intermittent renewable energy for use during peak times. A detailed control-volume energy analysis of the system is carried out, yielding a set of coupled differential equations which are discretized using a finite difference scheme and used to model the transient response during charging and discharging. The energy analysis includes coupled heat transfer and pressure drop analysis used to predict system losses for more accurate round trip efficiency (RTE) calculations and specific energy density (ED) predictions. Preliminary analysis of the current prototype indicates an electric-to-electric RTEE of 66% (corresponding to shaft-to-shaft mechanical RTEM of 78%) and ED of 2.5 MJ/m3 of air, given initial air volume and pressure of 2 m3 and 70 bar. The electric power output ranges from a max of 2.5 kW to a min of 1.2 kW and the output current ranges from a max of approximately 21 amps to approximately 10 amps at 120 V, 60 Hz dispatchable electricity, over a period of approximately 50 minutes. Additionally, it is shown that heat transfer enhancement to the point of a 5-fold increase in air heat transfer rates results in a near 5% improvement in RTEE (70% considering all component losses). Additional component efficiency improvements and efficiency gains due to system scale-up could see higher achievable RTEs.Copyright

Thermofluid Analysis of the Magnetocaloric Refrigeration

While there have been extensive studies on thermofluid characteristics of different magnetocaloric refrigeration systems, a conclusive optimization study using non-dimensional parameters which can be applied to a generic system has not been reported yet. In this study, a numerical model has been developed for optimization of active magnetic refrigerator (AMR). This model is computationally efficient and robust, making it appropriate for running the thousands of simulations required for parametric study and optimization. The governing equations have been non-dimensionalized and numerically solved using finite difference method. A parametric study on a wide range of non-dimensional numbers has been performed. While the goal of AMR systems is to improve the performance of competitive parameters including COP, cooling capacity and temperature span, new parameters called “AMR performance index-1” have been introduced in order to perform multi objective optimization and simultaneously exploit all these parameters. The multi-objective optimization is carried out for a wide range of the non-dimensional parameters. The results of this study will provide general guidelines for designing high performance AMR systems.Copyright

Experimental Study on Performance of a Residential Combined Cooling, Heating and Power System Under Varying Building Load

Trigeneration systems are closely associated with sorption cooling technology because prime mover waste heat can be recovered to produce cooling. The working pair and cycle type of the sorption cooling system needs to be matched to the waste heat temperature of the prime mover, as well as with the capacity and application of the trigeneration system. A residential trigeneration system with a 4 kWelec internal combustion engine, a 220 gallon (830 L) hot water tank and a 3 kW adsorption chiller powered by 70°C waste heat with separate sensible and latent cooling control strategy is presented in this study. Transient experiments were conducted under 5 day long hot water and space cooling load profiles from a simulated house to evaluate the performance from a practical perspective. The fuel consumption was measured and compared with that of two baseline systems. An analytical criterion was derived and discussed to further evaluate the trigeneration system with different loads under different climates. It was found that the presented residential trigeneration system could save about 30% of fuel consumption compared with conventional off-grid operation mode, but is not more fuel efficient than the conventional on-grid and vapor compression cooling combination.Copyright

Overview of Resources for Geothermal Absorption Cooling for Buildings

This report summarizes the results of a literature review in three areas: available low-temperature/coproduced geothermal resources in the United States, energy use for space conditioning in commercial buildings, and state of the art of geothermal absorption cooling.

Preliminary Investigation of Novel Direct Contact Ultrasonic Fabric Drying

Thermal evaporation of moisture from clothes is the main technique used in clothes dryers today. Most of the energy supplied is spent to provide the latent heat of evaporation of water (2.5MJ/kg). This paper presents a novel direct contact ultrasonic system to mechanically remove water from wet fabric. The vibrations from the transducers are transferred by direct contact to the water inside the narrow pores of the clothes. Breaking the capillary adhesion of moisture at the interface between air and water allows water to exit the clothes as cold mist. The cold mist also carries with it most impurities such as minerals or detergents. This cannot be achieved in thermal dryers where water evaporates and leaves the impurities behind. Mechanical extraction of water is expected to be more efficient since thermal processing is not required. The majority of the supplied energy is used to mechanically separate water from the fabric. Initial testing has revealed that it is possible to dry a 1 cm2 piece of fabric from full saturation to a mere 0.4 % moisture content in just 14 seconds.Copyright