ISHPC 2021 proceedings – online pre-conference 2020

For decades there has been intense research and development on sorption heat pumping and cooling processes; still, looking at the sales numbers, it is mainly a niche technology. The current transition to an energy system based on renewables changes the boundary conditions. Sorption heat pumps will have an indispensable place in this context, especially for its potential to make use of waste heat. We want to look at the future of sorption heat pumping devices including the newest research developments, as well as reports about pilots and mature technology

Optimization of empirical typhoon model considering the difference of radius between pressure gradient and wind speed distributions

This study proposes empirical relations for the ratio of the radius of maximum pressure gradient to the radius of maximum wind speed for the empirical typhoon model (ETM) based on the results of analysis of multiple typhoons obtained from the meteorological model. One proposed relation was parameterized based on the attenuation rate from the peak time to landfall time. The other was parameterized based on the distance from where the typhoon reached its peak intensity to the coastline. These relationships are useful for practical applications. In addition, the typhoon pressure shape parameter B was calculated from the constructed equations and the relational equation proposed by Holland. The improvement in accuracy, as compared with conventional ETM (B = 1, and B estimated by the gradient-wind equilibrium assumption), was determined for three cases of typhoons making landfall in Japan in recent years. As a result, it was confirmed that the proposed equations for parameter B are the most accurate amongst the three estimation methods. Accordingly, the improvement in the accuracy of the ETM using the estimation equations was validated. When using the ETM in the future, high accuracy can be realized by utilizing the estimation equations used in this study

Simulation of a solid sorption ice-maker based on the novel composite sorbent "lithium chloride in silica gel pores"

In this paper, a novel composite sorbent "lithium chloride in silica gel pores” is proposed for application in solar-powered adsorptive ice makers. A mathematical model was used in order to calculate the performance of an ice-maker using this material as adsorbent and methanol as adsorbate. The results of the model showed that a maximum solar coefficient of performance (COPs) of 0.33 and a maximum daily ice production (DIP) of 20 kg/m2 can be obtained for an ice-maker equipped with a solar collector area of 1.5 m2 and 36 kg of adsorbent material. Such performance are noticeably higher than those obtained using commercial activated carbon, that is the adsorbent mostly proposed till now

Modelling of small capacity absorption chillers driven by solar thermal energy or waste heat

Aquesta recerca es centra en el desenvolupament de models en règim estacionari de màquines d’absorció de petita potència, els quals estan basats en dades altament fiables obtingudes en un banc d’assajos d’última tecnologia. Aquests models podran ser utilitzats en aplicacions de simulació, o bé per a desenvolupar estratègies de control de supervisió dels sistemes d’aire condicionat amb màquines d’absorció. Per tant, l’objectiu principal d’aquesta investigació és desenvolupar i descriure una metodologia comprensible i que englobi el procés sencer: tant els assajos, com la modelització, com també el desenvolupament d’una estratègia de control per a les màquines d’absorció de petita potència. Basant-se en la informació obtinguda de forma experimental en el banc d’assajos, s’han desenvolupat cinc models, cadascun amb una base teòrica diferent. Els resultats mostren que és possible obtenir models empírics summament precisos utilitzant únicament com a paràmetres d’entrada les variables dels circuits externs d’aigua. Aquest treball finalitza amb la proposta de dues estratègies òptimes de control i el seu ús per al control on-line de sistemes basats en refredadores tèrmiques d’absorció.This research deals with the development of the simple, yet accurate steady-state models of small capacity absorption machines which are based on highly reliable data obtained in the state-of-the-art test bench. These models can further be used in simulation tools or to develop supervisory control strategies for air-conditioning systems with absorption machines. Therefore, the main aim of this research is to develop and to describe a comprehensive methodology which encloses entire process which consists of testing, modelling and control strategy development of small capacity absorption machines. Five different models are developed based on the experimental data obtained in the test bench. The results show that it is possible to develop highly accurate empirical models by using only the variables of external water circuits as input parameters. Finally, two optimal control strategies are developed to demonstrate how these models can be used for on-line control of absorption systems

Heat transfer during the absorption of ammonia-rich vapor by aqueous solution inside a plate heat exchanger

Teil eines Wärmepumpenprozesses ist immer auch die Schnittstelle, an der die Wärme auf hohem Temperaturniveau wieder abgegeben wird. Als solche werden immer öfter Plattenwärmeübertrager eingesetzt, die gegenüber Rohrbündelwärmeübertragern vor allem kompakter und kostengünstiger sind. Es werden in der hier vorgestellten Versuchsanlage hauptsächlich Standardkomponenten eingesetzt, wodurch die Investitionskosten möglichst niedrig gehalten werden. Unter Verwendung des natürlichen Arbeitsstoffpaares Ammoniak und Wasser stellt die Kompressions-Wärmepumpe mit Lösungskreislauf ein vielversprechendes Konzept für typische industrielle Anwendungsszenarien dar. Der Einsatz eines Plattenwärmeübertragers als Fallfilm-Absorber ist bisher noch wenig untersucht und stellt daher den Inhalt der vorliegenden Arbeit dar. Denn der Absorber-Wärmeübertrager wurde generell in vorhergehenden Arbeiten als leistungsbestimmende Komponente ausgemacht und es besteht Bedarf an verlässlichen Auslegungskorrelationen für den Wärmeübergang und den damit verbundenen Druckverlust. Weiterhin wird unter Verwendung literaturbekannter Berechnungsansätze ein Simulationsmodell entwickelt, dessen Berechnungsergebnisse den experimentellen Daten gegenübergestellt werden.The interface at which heat is transferred to the heat sink at the high temperature level is always part of a heat pump process. Increasingly often plate heat exchangers are utilized as such being more compact and cost efficient than shell and tube heat exchangers. Keeping the investment cost low is one of the main goals of this project that includes the setup of a test rig constructed of mainly standard components. Using the combination of the natural working fluids ammonia and water the hybrid absorption compression heat pump concept is well suited for typical industrial applications. Since the implementation of a plate heat exchanger as a falling film absorber is yet to be investigated thoroughly it is the main purpose of this work. In general, the absorber has been determined as one of the key components of the setup and there is a need for reliable correlations to predetermine heat transfer and pressure loss. Furthermore, a simulation model is developed using calculation approaches available in the literature. The results are then compared to the experimental data.Bundesministerium für Wirtschaft und Energie/Energie/03ET1168A/E