Development of potential map for ground and groundwater heat pump systems and the application to Tokyo

It is necessary for optimum design of GSHP systems to estimate accurately thermal properties of the designed ground and predict the heat extraction rate from the ground. Generally, experimental analysis has been used for the feasibility of system introduction such as thermal response test, pumping test or cone penetrating test, but it causes to increase estimation cost before the introduction, equivalent to tens of thousands of dollars in Japan. On the other hand, the heat exchange rate and the effect of the system on underground environment can be predicted by using numerical simulation. In this research, in order to estimate the effect of the ground thermal properties on system performance, numerical simulation has been conducted through the sensitivity analysis with the developed simulation tool. Furthermore, the method to develop an energy potential for GSHP system has been suggested and its application for Tokyo 23 ward area has been conducted with GIS data.     

Numerical simulation of ground heat and water transfer for groundwater heat pump system based on real-scale experiment

The groundwater heat pump (GWHP) system is an open-loop system that draws water from a well or surface water, passes it through a heat exchanger and discharges the water into an injection well or nearby river. By utilizing the relatively stable temperature of groundwater, GWHP system can achieve a higher coefficient of performance and can save more energy than conventional air-source heat pump (ASHP) system. The performance of the system depends on the condition of groundwater, especially temperature and depth, which affect performance of the heat pump and system. For the optimization of design and operation of GWHP systems, it is necessary to develop a simulation tool which can predict groundwater and heat flow and evaluate system performance comprehensively. In this research, 3D numerical heat-water transfer simulation and experiments utilizing real-scale equipment has been conducted in order to develop the optimization method for GWHP systems. Simulation results were compared with the experimental results, and the validity of the simulation model was confirmed. Furthermore, several case studies for the optimal operation method have been conducted by calculating the coefficient of performance on various groundwater and well conditions.     

Optimization-based computation of analytic interpolants of bounded complexity

This paper provides a unifying algorithm for computing any analytic interpolant of bounded complexity. Such computation can be performed by solving an optimization problem, due to a theorem by Georgiou and Lindquist. This optimization problem is numerically solvable by a continuation method. The proposed numerical algorithm is useful, among other cases, for designing a low-degree controller for a benchmark problem in robust control. The algorithm unifies previously developed algorithms for the Carathéodory extension and the Nevanlinna–Pick interpolation to one for more general interpolation problems.     

Radiative heat transfer by flowing multiphase medium-part I. An analysis on heat transfer of laminar flow between parallel flat plates

The multiphase flow of gaseous suspensions of fine particles furnishes high heat transfer characteristics at high and/or extremely high temperatures and at high heat fluxes due to the radiative transfer from heat source to suspensions. The phaseshift of particulate medium improves the overall heat transfer remarkably and from the practical viewpoint there exists important relevance pertinent to the industrial applications.

It is worth having a closer look at the behaviors of the suspensions and the heat transfer mechanism in flowing multiphase media so that the discussions are held concerning the foregoing media in some details.

An analysis is carried out on the laminar flow between parallel plates by taking into account of thermal radiation and the results illustrate the temperature profiles of fluid and dispersed phase, respectively, and the heat transfer characteristics for the wide ranges of dimensionless parameters such as conduction y, and radiation interaction parameter, loading ratio of particles, optical depth of duct, heat transfer between the two phases and so forth. Reference to the temperature profiles reveals the facts that while the temperature gradient in the vicinity of the heating surface increases due to the presence of particulate phase, the cupmixing mean temperature is raised appreciably by thermal radiation through the dispersed medium. In consequence, the contributions of suspensions on heat transfer are drastic, particularly in high temperature cases. Alternatively the correlations between the foregoing dimensionless parameters are also examined in current study.     

Bromide removal by hydrotalcite-like compounds in a continuous system.

Bromide ion removal from a real water matrix by hydrortalcite-like compounds (HTCs) was attempted in a column reactor to control the formation of brominated disinfection by-products in drinking water treatment process. The performance of HTCs was found to be comparable to a commercially available ion exchange resin for relatively low alkalinity water. Also, it was deduced that HTCs are better than ion exchange resins for high sulfate water because of their unique ion selectivity. In addition, the ion exchange reactions by HTCs were faster than a commercially available resin. Thus, HTCs are expected to provide similar performance to organic resins without the concern about secondary contamination (i.e., elution of organic compounds from resins).     

Experimental study on multi-layered type of gas-to-gas heat exchanger using porous media

Based on an effective energy conversion method between flowing gas enthalpy and thermal radiation, a multi-layered type of gas-to-gas heat exchanger using porous media has been proposed. A series of experiments have been conducted for the inlet temperature of high temperature gas 300-700 °C, the optical thickness of porous media 0-15.4, the number of layers 2-5 and two types of walls (bare or finned) placed in the system. As a result, a heat recovery section is shown to play an important role in lowering an outer wall temperature of the system and at the same time in increasing the total heat recovery rate H_tot,N. In addition, it is clarified that the optical thickness of about 8 is enough to obtain sufficient H_tot,N, and the finned walls are quite effective to promote H_tot,N under the present experimental conditions.     

Complementary Scaling For Cross-National Analyses Of National Character

This paper discusses different methods of measuring and comparing national character cross-nationally, considered respectively in terms of a multifaceted phenomenon and a specific aspect such as the quality of life. Using data collected in seven nations, we first applied the GHT model with VA representations to both a global and a specific pool of quality of life items, making use of the concept of “superculture” as a basis of comparison among countries. We then undertook principal components analysis for another global pool of items and the quality of life items, comparing the structure of different attitudes and the substantive level of quality of life among countries. The substantive results of the different methods of analyses concurred in some respects and differed in others. Importantly, the paper underscored the complementarity of different methods as equally fruitful ways to understanding national character in a cross-national context.

     

Multi-variable Optimization of HVAC System Using a Genetic Algorithm

Geothermal is a fast-growing alternative heat source for HVAC systems, however, the initial cost of using a ground source HVAC system is higher compared to an air source system. Studies about system design and operation are necessary to reduce the initial cost and ensure that the ground source heat pump system has high efficiency, resulting in a lower total life-time cost. In this study, a multi-variable evolutionary computation algorithm is proposed for generating optimal parameters for a geothermal source HVAC system. The system was modeled and simulated using MATLAB. The design parameters were calculated by minimizing the energy consumption, Based on an experimental building, a case study was presented. Using this model, the optimal set points were calculated and used as a designed system. Energy consumption of this system was reduced by about 10% compared to the system operated with a fixed supply cold water temperature （7 ℃）.     

CONVENTIONAL BASIC DESIGN FOR CONVECTION OR CONDUCTION DRYERS

Abstract

The items to be considered prior to selection of dryers are explained, and a simple method for a rough estimation of dryer sizes was proposed based on data obtained from operating industrial dryers.

The equations of basic design for batch or continuous type dryers were derived. The heat was supplied to materials by convection and/or conduction. The equations were simplified to the case when the falling rate of drying is proportional to the moisture content of materials under the constant drying conditions. The heat transfer coefficient used in the equations can be determined based on the calculations or the data obtained from the experimental or industrial dryers. The equations are useful for estimating the scale-up effect of dryers.