11 documents found, page 1 of 2
On the best coefficient of performance and specific heating or cooling power co...
Costa, Vítor A. F.; Dias, João M. S.The performance parameters of adsorption refrigerators or heat pumps are the coefficient of performance (COP) and the specific cooling power (SCP) or specific heating power (SHP), respectively. Higher COPs are associated with the longer cycle times required for more complete desorption and adsorption processes, resulting in a lower number of cycles per unit time and consequently in lower SCP or SHP, unless larg...
Modelling and analysis of a complete adsorption heat pump system
Dias, João M. S.; Costa, Vítor A. F.Adsorption heat pumps (AHPs) can play a significant role in the future energy transition policies. However, the technology still needs to be matured and further research is still necessary. In this paper, the detailed model of a whole AHP system for domestic water heating is presented aiming to fulfil the literature gap for models that can simulate the dynamics of these complete heating systems, while maintaini...
Virtual test bench for the design of control strategies for water heaters
Quintã, André F.; Oliveira, Jonathan D.; Ferreira, Jorge A. F.; Costa, Vítor A. F.; Martins, N.An innovative methodology and a virtual test bench (VTB) are proposed to support the design of water heaters’control strategies. This platform allows to speed up the development and evaluation of control systems even before the existence of prototypes or real test environments. By simulating the environmental conditions and the state of the different device components, it will be possible to detect and correct ...
Adsorption cooler design, dynamic modeling, and performance analyses
Dias, João M. S.; Costa, Vítor A. F.This paper presents an adsorption cooler (AC) driven by the surplus heat of a solar thermal domestic hot water system to provide cooling to residential buildings. A cylindrical tube adsorber using granular silica gel as adsorbent and water as adsorbate was considered. The AC was modelled using a two-dimensional distributed parameter model implemented in previous adsorption heating and cooling studies. The perfo...
Modeling and analysis of a coated tube adsorber for adsorption heat pumps
Dias, João M. S.; Costa, Vítor A. F.This work investigates the effects of several parameters on the coefficient of performance (COP) and the specific heating power (SHP) of a coated-tube adsorber for adsorption heat pumps (AHP) suitable for water heating (space and/or domestic water heating). The COP and SHP are obtained based on physical models that have already been proven to adequately describe this type of adsorber. Several parameters are tes...
Evaluating the performance of a coated tube adsorber for adsorption cooling
Dias, João M. S.; Costa, Vítor A. F.Adsorption cooling (AC) is an environmentally friendly alternative to conventional vapor compression cooling. In this paper, the performance of a coated tube adsorber suitable for AC systems is numerically evaluated. The developed adsorber uses silica gel-water as adsorbent-adsorbate working pair. A numerical model is used to analyze the influence of several governing parameters such as the evaporator, condense...
Performance Analysis of a Solar DHW System with Adsorption Module Operating in ...
Fernandes, Marco S.; Costa, Vítor A. F.; Brites, Gonçalo J. V. N.; Gaspar, Adélio R.; Costa, José J.A numerical study was conducted on the performance of a solar domestic hot water storage system with an adsorption module operating in seven di erent world locations. The base system was optimized for Portuguese conditions and, without changing the system itself and the water consumption profile, its performance was investigated by altering local installation and operating conditions and solar collector inclina...
Which dimensional model for the analysis of a coated tube adsorber for adsorpti...
Dias, João M. S.; Costa, Vítor A. F.This paper presents the analysis of a coated tube adsorber for adsorption heat pumps (AHP), starting from a well-established physical model and providing information on how many dimensions need to be considered for a given accuracy. A lumped-parameter model, one-dimensional (radial direction) and two-dimensional (radial and longitudinal directions) distributed-parameter models describing the adsorber's dynamics...
Simulation models for tankless gas water heaters
Quintã, André F.; Ferreira, Jorge A. F.; Ramos, António; Martins, Nelson A. D.; Costa, Vítor A. F.There is a growing concern about to the scarceness of natural resources and the emissions problematic. Water heating is a relevant part of a household’s energy use, and tankless gas water heaters (TGWH) are widely used. There are design and engineering challenges to develop more efficient devices, with lower emissions of pollutant gases and providing comfort improvements from the user point of view. The main ob...
Adsorption heat pumps for heating applications: A review of current state, lite...
Dias, João M. S.; Costa, Vítor A. F.A review of the most relevant work on the field of adsorption heat pumps with emphasis on heating applications is presented, covering the working principle, physical models, adsorption equilibrium and kinetics, adsorbent material physical and thermodynamic properties, adsorbent bed designing and operating conditions. The major literature gaps and development challenges of adsorption heat pumps for heating appli...