Aqueous Lithium Bromide TES and R-123 Chiller in Series

2003 ◽  
Vol 125 (1) ◽  
pp. 49-54 ◽  
Author(s):  
J. J. Rizza
Keyword(s):  
Heat Pump ◽  
Liquid Water ◽  
Lithium Bromide ◽  
Water System ◽  
Internal Heat ◽  
Thermal Storage ◽  
Volumetric Efficiency ◽  
Peak Period ◽  
Water Ice ◽  
In Series

This paper presents an analysis of a cold thermal energy storage (TES) system operating in series with an R-123 chiller. A lithium bromide/water LiBr/H2O solution is used both as a refrigerant and as a cold thermal storage material. The refrigerant, liquid water, is extracted from the LiBr/H2O strong solution during the off-peak period. The liquid water and LiBr/H2O weak solution, a byproduct of the refrigerant recovery process, are used during the on-peak period to cool the building. Building waste heat is pumped by the R-123 compressor to a higher temperature during the off-peak period and is used in the generator to recover the thermal storage by reprocessing the stored solution to a higher lithium bromide concentration. The storage volumetric efficiency and system COP are determined and compared to storage systems based on water/ice and liquid water. The storage volumetric efficiency is greater than a water/ice system and far exceeds the value for a liquid water system. The proposed system, which uses an external heat pump as a source of generator heat, is also compared to another LiBr/H2O system that uses a self-contained internal heat pump (the compressor operates independently from the chiller and uses the liberated water refrigerant as its working fluid). The system presented here outperforms both the water/ice system and the internal heat pump LiBr/H2O system but is unable to match the liquid water system COP. However, it has other well-defined advantages over the liquid water system and appears to be a competitive alternative to conventional TES systems.

Lithium Bromide and Water Thermal Storage System

1988 ◽  
Vol 110 (4) ◽  
pp. 327-334 ◽  
Author(s):  
J. J. Rizza
Keyword(s):  
Heat Pump ◽  
Liquid Water ◽  
Water Solution ◽  
Storage System ◽  
Lithium Bromide ◽  
Water System ◽  
Thermal Storage ◽  
Volumetric Efficiency ◽  
Peak Period ◽  
Water Ice

An analysis of a thermal storage system using a lithium bromide and water solution both as a refrigerant and as a storage material is considered. The proposed thermal storage system can be used to shift electric demand from periods of high demand to periods of low demand. The system is considered for both the summer cooling and winter heating season. The system’s evaporator and absorber are similar to that of a conventional heat-operated absorption refrigeration system; however, the generator heat is supplied by a self-contained electrically-driven vapor compression heat pump. The heat pump is operated during the off-peak period to recover the thermal storage by reprocessing the stored solution to a higher lithium bromide concentration. The water vapor liberated from solution in the generator is compressed and then condensed in the generator. The storage volumetric efficiency is determined and compared to storage systems based on water ice for the cooling season only and on a liquid water storage system for both cooling and heating. The storage volumetric efficiency of the proposed system is greater than or comparable to that of a thermal storage system based upon water ice and far exceeds the value for a thermal storage system based upon liquid water. The system can be constructed from standard HVAC components and appears to be a competitive alternative to a water ice storage system for summer cooling only, and it could be a competitive alternative to a liquid water system for combined summer and winter operations.

Ammonia-Water Low-Temperature Thermal Storage System

1998 ◽  
Vol 120 (1) ◽  
pp. 25-31 ◽  
Author(s):  
J. J. Rizza
Keyword(s):  
Low Temperature ◽  
Heat Pump ◽  
Water Solution ◽  
Storage System ◽  
Water Concentration ◽  
Thermal Storage ◽  
Ammonia Vapor ◽  
Peak Period ◽  
Ammonia Water ◽  
Absorption Refrigeration System

An analysis of a low-temperature thermal storage system using an ammonia-water solution both as a refrigerant and as a low-temperature thermal storage material is considered. The thermal storage is useable at a temperature of −27°C and higher. The proposed system is designed to shift electric demand from high to low-demand periods. The system utilizes a heat-operated absorption refrigeration system; however, the generator heat is supplied by a self-contained vapor compression heat pump. The heat pump is operated during the off-peak period to recover the low-temperature thermal storage by reprocessing the stored ammonia-water solution to a lower ammonia-water concentration. The ammonia vapor liberated from solution in the dephlegmator is used in the compressor to produce the generator heat. Three different configurations are considered, including a solar-assisted system. The results are compared to an eutectic salt storage system.

scholarly journals Optimal Operation of Low-Capacity Heat Pump Systems for Residential Buildings through Thermal Energy Storage

2021 ◽  
Vol 13 (13) ◽  
pp. 7200
Author(s):  
Alessandro Franco ◽  
Carlo Bartoli ◽  
Paolo Conti ◽  
Daniele Testi
Keyword(s):  
Heat Pump ◽  
Residential Buildings ◽  
Electric Energy ◽  
Thermal Storage ◽  
High Water ◽  
Energy Performance ◽  
Heat Emission ◽  
Optimal Operation ◽  
Pump Operation ◽  
In Series

The paper provides results from a hardware-in-the-loop experimental campaign on the operation of an air-source heat pump (HP) for heating a reference dwelling in Pisa, Italy. The system performances suffer from typical oversizing of heat emission devices and high water-supply temperature, resulting in HP inefficiencies, frequent on-off cycles, and relevant thermal losses on the hydronic loop. An experimentally validated HP model under different supply temperatures and part-load conditions is used to simulate the installation of a thermal storage between heat generator and emitters, in both series and parallel arrangements. Results relative to a typical residential apartment show that the presence of the thermal storage in series configuration ensures smoother heat pump operation and energy performance improvement. The number of daily on-off cycles can be reduced from 40 to 10, also saving one-third of electric energy with the same building loads. Preliminary guidelines are proposed for correctly sizing the tank in relation to the HP capacity and the average daily heating load of the building. A storage volume of about 70 L for each kilowatt of nominal heating capacity is suggested.

Lichens of the Oasis Molodyozhnyi and adjacent areas (Enderby Land, Antarctic)

2013 ◽  
Vol 47 ◽  
pp. 167-178 ◽  
Author(s):  
M. P. Andreev
Keyword(s):  
Liquid Water ◽  
Climate Conditions ◽  
Water Ice ◽  
Buellia Frigida ◽  
Antarctic Continent ◽  
Harsh Climate ◽  
The Antarctic ◽  
First Time ◽  
Lichen Flora

Lichen flora and vegetation in the vicinity of the Russian base «Molodyozhnaya» (Enderby Land, Antarctica) were investigated in 2010–2011 in details for the first time. About 500 specimens were collected in 100 localities in all available ecotopes. The lichen flora is the richest in the region and numbers 39 species (21 genera, 11 families). The studied vegetation is very poor and sparse, but typical for coastal oases of the Antarctic continent. The poorness is caused by the extremely harsh climate conditions, insufficient availability of liquid water, ice-free land, and high insolation levels. The dominant and most common lichens are Rinodina olivaceobrunnea, Amandinea punctata, Candelariella flava, Physcia caesia, Caloplaca tominii, Lecanora expectans, Caloplaca ammiospila, Lecidea cancriformis, Pseudephebe minuscula, Lecidella siplei, Umbilicaria decussata, Buellia frigida, Lecanora fuscobrunnea, Usnea sphacelata, Lepraria and Buellia spp.

DETERMINING THE PROFITABILITY OF GREENHOUSE ELECTROTECHNOLOGIES: A MODELING APPROACH

HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 249a-249
Author(s):  
Eric A. Lavoie ◽  
Damien de Halleux ◽  
André Gosselin ◽  
Jean-Claude Dufour
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Water System ◽  
Heat Pumps ◽  
Hot Water ◽  
Pump System ◽  
Heat Pump System ◽  
Artificial Lighting ◽  
Hot Air ◽  
Marketable Fruit

The main objective of this research was to produce a simulated model that permitted the evaluation of operating costs of commercial greenhouse tomato growers with respect to heating methods (hot air, hot water, radiant and heat pumps) and the use of artificial lighting for 1991 and 1992. This research showed that the main factors that negatively influence profitability were energy consumption during cold periods and the price of tomatoes during the summer season. The conventional hot water system consumed less energy than the heat pump system and produced marketable fruit yields similar to those from the heat pump system. The hot water system was generally more profitable in regards to energy consumption and productivity. Moreover, investment costs were less; therefore, this system gives best overall financial savings. As for radiant and hot air systems, their overall financial status falls between that of the hot water system and the heat pump. The radiant system proved to be more energy efficient that the hot air system, but the latter produced a higher marketable fruit yield over the 2-year study.

scholarly journals Developing a Cold Accumulator with a Capsule Bed Containing Water as a Phase-Change Material

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2703
Author(s):  
Robert Sekret ◽  
Przemysław Starzec
Keyword(s):  
Energy Efficiency ◽  
Heat Pump ◽  
Cold Storage ◽  
Cooling Capacity ◽  
Cooling Power ◽  
Storage Process ◽  
Water Ice ◽  
Measurement Results ◽  
Mathematical Relationships ◽  
Change Material

The paper presents the investigation of a prototype cold accumulator using water–ice latent heat for the cold storage process. The concept of the cold accumulator was based on a 200-L-capacity cylindrical storage tank in which spherical capsules filled with water were placed. Beds of polypropylene capsules with diameters of 80 mm, 70 mm, and 60 mm were used in the tests. The cold accumulator operated with a water–air heat pump. Based on the test results, the following parameters were calculated: the cooling capacity, cooling power, energy efficiency of the cold storage, and energy efficiency ratio (EER) of the accumulator. The obtained measurement results were described with mathematical relationships (allowing for measurement error) using criterial numbers and the developed “Research Stand Factor Number” (RSFN) index. It has been found that, for the prototype cold accumulator under investigation, the maximum values of the cooling capacity (17 kWh or 85.3 kWh per cubic meter of the accumulator), energy efficiency (0.99), and EER (4.8) occur for an RSFN of 144·10−4. The optimal conditions for the operation of the prototype cold accumulator were the closest to laboratory tests conducted for a bed with capsules with a diameter of 70 mm and a mass flow of the water–glycol mixture flowing between the accumulator and the heat pump of 0.084 kg/s. During the tests, no significant problems with the operation of the prototype cold accumulator were found.

Energy Consumption Modeling of a Heat Pump System for Combined Space Conditioning and Residential Water Heating in a Typical Household in Quito, Ecuador

2016 ◽  
Author(s):  
Gabriel Agila ◽  
Guillermo Soriano
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Thermal Storage ◽  
Hot Water ◽  
Water Heating ◽  
Water Heater ◽  
Pump System ◽  
Detailed Model ◽  
Heat Pump Water Heater ◽  
Residential Water

This research develops a detailed model for a Water to Water Heat Pump Water Heater (HPWH), operating for heating and cooling simultaneously, using two water storage tanks as thermal deposits. The primary function of the system is to produce useful heat for domestic hot water services according to the thermal requirements for an average household (two adults and one child) in the city of Quito, Ecuador. The purpose of the project is to analyze the technical and economic feasibility of implementing thermal storage and heat pump technology to provide efficient thermal services and reduce energy consumption; as well as environmental impacts associated with conventional systems for residential water heating. An energy simulation using TRNSYS 17 is carried to evaluate model operation for one year. The purpose of the simulation is to assess and quantifies the performance, energy consumption and potential savings of integrating heat pump systems with thermal energy storage technology, as well as determines the main parameter affecting the efficiency of the system. Finally, a comparative analysis based on annual energy consumption for different ways to produce hot water is conducted. Five alternatives were examined: (1) electric storage water heater; (2) gas fired water heater; (3) solar water heater; (4) air source heat pump water heater; and (5) a heat pump water heater integrated with thermal storage.

Experimental performance study on a dual-mode CO2 heat pump system with thermal storage

2017 ◽  
Vol 115 ◽  
pp. 393-405 ◽  
Author(s):  
Fang Liu ◽  
Weiquan Zhu ◽  
Yang Cai ◽  
Eckhard A. Groll ◽  
Jianxing Ren ◽  
...  
Keyword(s):  
Heat Pump ◽  
Thermal Storage ◽  
Performance Study ◽  
Dual Mode ◽  
Pump System ◽  
Heat Pump System ◽  
Experimental Performance
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