scholarly journals Systematic Renovation Design of Surface Water Source Heat Pump for a Hot Spring Center Based on Thermodynamic Analysis

2021 ◽  
Vol 39 (3) ◽  
pp. 1026-1036
Author(s):  
Yijun Liu
Keyword(s):  
Surface Water ◽  
Optimization Design ◽  
Cold Water ◽  
Waste Heat ◽  
Hot Spring ◽  
Water System ◽  
Operating Conditions ◽  
Hot Water ◽  
Total Energy Consumption ◽  
Spring System

Currently, the application and renovation of surface water heat source pump (WHSP) mainly attempt to optimize heat exchangers, water pumps, the overall system, and economic frictional head loss. The mathematical model is often established and solved with such optimization objectives as optimization parameters, control forms, costs, and feasibility of investment and construction. There are relatively few studies that optimize the operating conditions with the minimal total energy consumption of system operations, and, on this basis, pursue global optimization design of the WSHP system. Therefore, this paper aims to carry out a systematic renovation design of the surface WSHP in a hot spring center in the national forest park of northern Guilin, southwestern China’s Guangxi Zhuang Autonomous Region. The project mainly covers the design of hot spring system, air-conditioning system, and hot water system, as well as the exergy analysis of WSHP system. Among them, the design of hot spring system includes the regulation of raw water, cold water, and warmed water; the constant temperature control of hot spring pools; the waste heat utilization of warmed water from the pools. The scientific nature of the design was proved through experiments.

Design and Performance of a Fuel Cell Plant Heat Recovery System

2007 ◽  
Author(s):  
Robert G. Ryan ◽  
Tom Brown
Keyword(s):  
Fuel Cell ◽  
Latent Heat ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Operating Conditions ◽  
Hot Water ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

A 1 MW Direct Fuel Cell® (DFC) power plant began operation at California State University, Northridge (CSUN) in January, 2007. This plant is currently the largest fuel cell plant in the world operating on a university campus. The plant consists of four 250 kW DFC300MA™ fuel cell units purchased from FuelCell Energy, Inc., and a waste heat recovery system which produces dual heating hot water loops for campus building ventilation heating, and domestic water and swimming pool heating water for the University Student Union (USU). The waste heat recovery system was designed by CSUN’s Physical Plant Management and engineering student staff personnel to accommodate the operating conditions required by the four individual fuel cell units as well as the thermal energy needs of the campus. A Barometric Thermal Trap (BaTT) was designed to mix the four fuel cell exhaust streams prior to flowing through a two stage heat exchanger unit. The BaTT is required to maintain an appropriate exhaust back pressure at the individual fuel cell units under a variety of operating conditions and without reliance on mechanical systems for control. The two stage heat exchanger uses separate coils for recovering sensible and latent heat in the exhaust stream. The sensible heat is used for heating water for the campus’ hot water system. The latent heat represents a significant amount of energy because of the high steam content in the fuel cell exhaust, although it is available at a lower temperature. CSUN’s design is able to make effective use of the latent heat because of the need for swimming pool heating and hot water for showers in an adjacent recreational facility at the USU. Design calculations indicate that a Combined Heat and Power efficiency of 74% is possible. This paper discusses the integration of the fuel cell plant into the campus’ energy systems, and presents preliminary operational data for the performance of the heat recovery system.

scholarly journals Non-residential water demand model validated with extensive measurements and surveys

2013 ◽  
Vol 6 (2) ◽  
pp. 99-114 ◽  
Author(s):  
E. J. Pieterse-Quirijns ◽  
E. J. M. Blokker ◽  
E. van der Blom ◽  
J. H. G. Vreeburg
Keyword(s):  
Water Demand ◽  
Cold Water ◽  
Residential Buildings ◽  
Water System ◽  
Hot Water ◽  
Demand Model ◽  
Water Heater ◽  
Peak Demand ◽  
Demand Equations ◽  
Proper Estimation

Abstract. Existing Dutch guidelines for the design of the drinking water and hot water system of non-residential buildings are based on outdated assumptions on peak water demand or on unfounded assumptions on hot water demand. They generally overestimate peak demand values required for the design of an efficient and reliable water system. Recently, a procedure was developed based on the end-use model SIMDEUM to derive design-demand-equations for peak demand values of both cold and hot water during various time steps for several types and sizes of non-residential buildings, viz. offices, hotels and nursing homes. In this paper, the design-demand-equations are validated with measurements of cold and hot water patterns on a per second base and with surveys. The good correlation between the simulated water demand patterns and the measured patterns indicates that the basis of the design-demand-equations, the SIMDEUM simulated standardised buildings, is solid. Surveys were held to investigate whether the construction of the standardised buildings based on the dominant variable corresponds with practice. Surveys show that it is difficult to find relationships to equip the standardised buildings with users and appliances. However, the validation proves that with a proper estimation of the number of users and appliances in only the dominant functional room of the standardised buildings, SIMDEUM renders a realistic cold and hot water diurnal demand pattern. Furthermore, the new design-demand-equations based on these standardised buildings give a better prediction of the measured peak values for cold water flow than the existing guidelines. Moreover, the new design-demand-equations can predict hot water use well. In this paper it is illustrated that the new design-demand-equations lead to reliable and improved designs of building installations and water heater capacity, resulting in more hygienic and economical installations.

Occurrence of heterotrophic bacteria and fungi in cold and hot water distribution systems using water of different quality

1995 ◽  
Vol 41 (12) ◽  
pp. 1088-1094 ◽  
Author(s):  
Outi M. Zacheus ◽  
Pertti J. Martikainen
Keyword(s):  
Surface Water ◽  
Water Samples ◽  
Distribution Systems ◽  
Heterotrophic Bacteria ◽  
Cold Water ◽  
Hot Water ◽  
Thermophilic Fungi ◽  
Cell Counts ◽  
Bacteria And Fungi ◽  
Water Plants

The microbiological quality of cold and hot water samples of 67 Finnish buildings was studied. Most of the buildings were apartment buildings receiving their cold water from municipal groundwater or surface water plants. Disinfection with chlorine was applied in all the surface water plants and 33% of the groundwater plants. Water samples in buildings were taken from incoming cold water, from the hot water main just before and after the heat exchanger, and from a tap or shower in an apartment. The viable counts of mesophilic bacteria and fungi and total cell counts were higher in cold than in hot water samples. In hot water, the microbial counts were higher in samples from taps and showers than from the mains. In taps and showers, the decrease in hot water temperature probably increased the microbial numbers. Thermophilic bacteria appeared with high numbers in all the hot water samples, but thermophilic fungi were found in only one sample. Bacterial biomass and mean cell volume were greater in processed surface water than in processed groundwater samples. Disinfection with chlorine reduced the viable plate counts, although the chlorine concentration was extremely low in the water samples studied.Key words: heterotrophic bacteria, fungi, distribution system, groundwater, surface water.

scholarly journals Hydrochemical Characteristics and Multivariate Statistical Analysis of Natural Water System: A Case Study in Kangding County, Southwestern China

2017 ◽  
Author(s):  
Yunhui Zhang ◽  
Mo Xu ◽  
Xiao Li ◽  
Jihong Qi ◽  
Qiang Zhang ◽  
...  
Keyword(s):  
Surface Water ◽  
Natural Water ◽  
Thermal Water ◽  
Cold Water ◽  
Human Life ◽  
Water System ◽  
Anthropogenic Activity ◽  
Multivariate Statistical ◽  
Water Fraction ◽  
Deep Circulation

The utilization for water resource has been of great concern to human life. To assess the natural water system in Kangding County, the integrated methods of hydrochemcial analysis, multivariate statistics and geochemical modelling were conducted on surface water, groundwater and thermal water samples. Surface water and groundwater were dominated by Ca-HCO3 type, while thermal water belonged to Ca-HCO3 and Na-Cl type. The analyzing results concluded the driving factors that affect hydrochemical components. Following the results of the combined assessments, hydrochemcial process was controlled by the dissolution of carbonate and silicate minerals with slight influence from anthropogenic activity. The mixing model of groundwater and thermal water was calculated using silica-enthalpy method, yielding cold-water fraction of 0.56-0.79 and estimated reservoir temperature of 130-199 oC, respectively. δD and δ18O isotopes suggested surface water, groundwater and thermal springs were of meteoric origin. Thermal water should have deep circulation through the Xianshuihe fault zone, while groundwater flows through secondary fractures where it recharges with thermal water. Those analytical results were used to construct a hydrological conceptual model, providing a better understanding of the natural water system in Kangding County.

scholarly journals Numerical Simulations of Temperature and Velocity Fields in the Storage Tank with the Three-Coil Heat Exchanger

2020 ◽  
Vol 44 (3) ◽  
pp. 74-79
Author(s):  
Robert Smusz ◽  
Joanna Wilk ◽  
Paweł Bałon
Keyword(s):  
Numerical Simulations ◽  
Storage Tank ◽  
Thermal Stratification ◽  
Waste Heat ◽  
Velocity Fields ◽  
Operating Conditions ◽  
Hot Water ◽  
Water Storage Tank ◽  
Coil Heat Exchanger ◽  
Temperature And Velocity Fields

AbstractThis article presents the results of the numerical investigation of the thermal stratification in the hot water storage tank. The exchanger consists of three tube coils that are immersed in the storage tank of hot water. Two coils—lower and upper—are designed to warm the water in the tank using the water as a heating medium. Another coil—uses the refrigerant for the waste heat transfer. The temperature stratification device is mounted in the thermal storage tank. The device’s task is to improve the thermal stratification level of heated water. The performed numerical simulations allowed us to obtain the temperature and velocity fields in the storage tank under the conditions of the work of coils filled with water. Calculations were made in the case of the use of the stratification device under the operating conditions of the upper and lower coils with water.

scholarly journals Application research of intelligent monitoring system of longsheng hot spring water temperature based on Internet of Things

2019 ◽  
Vol 23 (5 Part A) ◽  
pp. 2613-2622
Author(s):  
Bi Li ◽  
Shi Zheng
Keyword(s):  
Water Temperature ◽  
Monitoring System ◽  
Hot Springs ◽  
Cold Water ◽  
Hot Spring ◽  
Spring Water ◽  
Temperature Monitoring ◽  
Hot Water ◽  
Single Chip ◽  
Main Station

Guangxi Guilin area, China, is rich in hot spring resources. In this paper, a hot spring water temperature monitoring system is developed for longsheng hot springs. Mainly using the hot water of eye of hot springs as the heat source, designing a set of multi-point temperature monitoring system with single-chip and multi-slave as the core of the single-chip microcomputer and wireless and bi-directional transmission for the main station and multiple slave stations to realize automatic temperature monitoring. The system slave station can exchange geothermal water with high temperature extracted from the eye of hot springs and cold water, and automatically control the temperature of the hot spring pool to reach a set value range by controlling the flow rate of the cold water. At the same time, the main station can complete the tasks of monitoring system by setting control commands such as temperature.

scholarly journals Experimental determination of cold water temperature at the inlet to solar water storage tanks

2019 ◽  
Vol 116 ◽  
pp. 00106 ◽  
Author(s):  
Miroslaw Zukowski
Keyword(s):  
Water Temperature ◽  
Cold Water ◽  
Tap Water ◽  
Water System ◽  
District Heating ◽  
Hot Water ◽  
Storage Tanks ◽  
Climate Conditions ◽  
Cold Water Temperature

In the present work, results of experimental research on the mains water temperature supplying the Solar Domestic Hot Water system in the period from 2016 to 2018 are shown. The test object is located in the Hotel for Research Assistants on Bialystok University of Technology campus in Poland. One of the elements that will guarantee the correct energy balance of a hot tap-water system is the exact determination of the cold water temperature. The aim of this study is estimation of the temperature of the mains water flowing into the district heating substation and the water feeding directly the heat storage tanks. The research results showed that the average value of the cold water was 14.09°C during the 3 years of measurements. Moreover, it was shown that this temperature increased by about 0.4°C as a result of heat exchange with the air inside the substation. In the article, the author proposed modifications of coefficients in a commonly used model developed by National Renewable Energy Laboratory for determining the temperature of mains water in energy simulations. The proposed changes allow for accurate modelling of the cold water temperature under the climate conditions of north-eastern Poland.

scholarly journals Dynamic experimental analysis of a LiBr/H2O single effect absorption chiller with nominal capacity of 35 kW of cooling

2019 ◽  
Vol 41 (1) ◽  
pp. 35173 ◽  
Author(s):  
Alvaro Antonio Ochoa Villa ◽  
José Carlos Charamba Dutra ◽  
Jorge Recarte Henríquez Henríquez ◽  
Carlos Antonio Cabral do Santos ◽  
José Ângelo Peixoto da Costa
Keyword(s):  
Thermal Load ◽  
Heat Dissipation ◽  
Cold Water ◽  
Operating Conditions ◽  
Hot Water ◽  
Experimental Methodology ◽  
Absorption Chiller ◽  
Water Heater ◽  
Nominal Capacity ◽  
Single Effect

This work aims to transient performance of chiller single effect absorption refrigeration using the LiBr/H2O pair with nominal capacity of 35 kW. The goal of this study is to verify the absorption chiller when subjected to thermal loads and it transiently responsive as a function of the temperatures of the chilled, hot and cold water of the system. An experimental methodology was established in a micro-CHP laboratory to simulate the dynamic operating conditions of the system considering the thermal load (chilled water), the activation source (hot water) and the heat dissipation circuit (cold water). The thermal load was simulated from a set of electrical resistors installed in a water heater and the activation of the chiller from recovery gas a microturbine 30 kW and through a compact heat exchanger, where water is heated and stored in a hot buffer tank. The absorption chiller heat dissipation system consists of the pump and cooling tower. The system responded appropriately to the thermal load imposed providing COP values in the transient regime of 0.55 to 0.70 the temperature conditions tested.

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