Energy and Cost Analysis of an Integrated Photovoltaic and Heat Pump Domestic System Considering Heating and Cooling Demands

The integration of photovoltaic panels and heat pumps in domestic environments is a topic that has been studied extensively. Due to their electrical nature and the presence of elements that add thermal inertia to the system (water tanks and the building itself), the functioning of compression heat pumps can be manipulated to try to fulfill a certain objective. In this paper, following a rule-based control concept that has been identified in commercial solutions and whose objective is to improve the self-consumption of the system by actively modulating the heat pump compressor, a parametric analysis is presented. By making use of a lab-tested model, the performance of the implemented control algorithm is analyzed. The main objective of this analysis is to identify and quantify the effects of the main parameters in the performance of the system, namely the climate (conditioning both heating and cooling demands), the photovoltaic installation size, the thermal insulation of the building and the control activation criteria. A total of 168 yearly simulations have been carried out. The results show that the average improvement in self-consumption is around 13%, while the cost is reduced by 2.5%. On the other hand, the heat from the heat pump and the power consumed increase by 3.7% and 5.2%, respectively. Finally, a linear equation to estimate the performance of the controller is proposed.This publication is part of the R+D+i project PID2021-126739OB-C22, financed by MCIN/AEI/10.13039/501100011033/ and “ERDF A way of making Europe”. Also, it has been financed by the Basque Business Development Agency (SPRI) in the 2020–2022 period in the projects ZL-2020-00379, ZL-2021-00225 and ZL-2022-00644 (BEROGRID); and by the Basque Government under the BIKAINTEK 2019 program

Hybrid liquid desiccant system: design and simulation models and experimental validation

The treatment of humidity on HVAC systems is crucial when a satisfactory indoor air quality needs to be reached. Traditional HVAC systems meet the latent cooling load by reducing the air temperature until its dew point, heating subsequently the air in order to reach the supply temperature for user comfort, with the energy waste this entails. On the other hand desiccant wheels requires normally an excessive post-cooling because of employed regeneration temperatures of around 70-80 ºC. In this paper the design and simulation models and testing results at laboratory scale of a hybrid liquid desiccant system (HLDS), developed in the frame of the EU project nanoCOOl, are presented. The HLDS is especially suited for applications with a low SHR (Sensible Heat ratio) and high ventilation requirements in tropical or subtropical climates. The aim of the project is to validate the developed technology for a good indoor environment quality, achieving the required ventilation needs, a good occupant comfort by the treatment of temperature and humidity to reach comfort conditions, avoiding the generation of moulds and microbial growth due to the antimicrobial properties of the LiCl. Detailed models of the HLDS components have been implemented in Engineering Equation Solver (EES) [1], and the whole model of the prototype has been developed, as well. The key parameters for the simulated HLDS, H&MTC (Heat&Mass transfer coefficients) have been experimentally obtained, testing the proof of concept absorber /regenerator in a test bench specially developed at laboratory scale[2]. The obtained values are in agreement with the correlations proposed by Bykov [3] (HTC) and Queiroz [4] (MTC).The research leading to these results has received funding from the European Union's Seventh Framework Programme FP7/2007-2013 under grant agreement n° 314701 (Nanocool project)