scholarly journals Dynamic Modelling and Validation of an Air-to-Water Reversible R744 Heat Pump for High Energy Demand Buildings

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8238
Author(s):  
Paolo Artuso ◽  
Giacomo Tosato ◽  
Antonio Rossetti ◽  
Sergio Marinetti ◽  
Armin Hafner ◽  
...  
Keyword(s):  
Experimental Data ◽  
Heat Pump ◽  
Energy Demand ◽  
High Energy ◽  
Hot Water ◽  
Inlet Temperature ◽  
Variable Load ◽  
Water Tank ◽  
Heat Flow Rate ◽  
Domestic Hot Water

This paper presents a reversible heat pump based on CO2 as the refrigerant, able to provide heating, cooling, and domestic hot water to high energy demand buildings. The unit was developed and tested under the EU H2020 project MultiPACK, which has the main goal of assuring the market about the feasibility, reliability, and energy efficiency of CO2 integrated systems for heating and cooling and promoting a fast transition to low environmental impact solutions. Within the project, the confidence raising was performed by installation and monitoring of fully integrated state-of-the art CO2 systems in the Southern European Climate. With the aim of predicting the unit behaviour under variable load and boundary conditions, a dynamic model of the entire unit was developed with commercial software, considering actual components and the implemented control system and it was validated with experimental data, collected at the factory’s lab before commissioning. The validation against experimental data collected during operation as a heat pump demonstrated a maximum percentage difference between the experimental and predicted value of gas–cooler heat flow rate equal to +5.0%. A preliminary comparison with the experimental data in chiller configuration is reported, however further development was required to achieve a satisfactory validation. Lastly, the numerical model was utilized to simulate a typical operation in heat pump configuration with the system coupled with a hot water tank storage for the production of domestic hot water and space heating; the model predicts higher COP when operating in domestic hot water operation due to the lower water inlet temperature.

Design and Development of an Experimental Apparatus for Hardware-In-The-Loop Testing of Solar Assisted Heat Pump Systems

2021 ◽  
Author(s):  
George Benzion van Arnold ◽  
Weimin Wang
Keyword(s):  
Heat Pump ◽  
Hot Water ◽  
Water Withdrawal ◽  
Water Tank ◽  
Flow Paths ◽  
Domestic Hot Water ◽  
Labview Software ◽  
Experimental Apparatus ◽  
Hardware In Loop ◽  
Operational Modes

Abstract This paper presents an experimental apparatus designed and built to facilitate the study of solar-assisted heat pump (SAHP) systems using the hardware-in-loop methodology. The apparatus includes an 11.6kW capacity water-to-water heat pump, a 409L thermal storage tank, a 288L domestic hot water tank, two variable speed circulation pumps, and emulation hardware representing solar collectors and conditioned building space. A complex network of piping and electronic diverting valves is used to create various energy flow paths to support fifteen different operational modes for space heating, space cooling, domestic hot water generation, and energy storage charging. The apparatus is heavily instrumented for temperature and flow measurement. Controls and data acquisition are predominantly managed using National Instruments hardware and LabVIEW software. The experimental apparatus has been installed, commissioned, and tested. The basic functionality of control and operation has been verified through testing four different operational modes and domestic hot water withdrawal emulation. The experimental apparatus can be used not only as a platform for research on a multifunctional indirect expansion SAHP system, but also allow for similar testing of less-complex related SAHP configurations.

scholarly journals Influence of the quantity profile of the domestic hot water demand and the energy demand for the heating in a single-family house on the SCOP of the air-to-water heat pump

2018 ◽  
Vol 44 ◽  
pp. 00162 ◽  
Author(s):  
Kamil Skoneczny
Keyword(s):  
Energy Efficiency ◽  
Heat Pump ◽  
Water Demand ◽  
Energy Demand ◽  
Hot Water ◽  
Single Family ◽  
Domestic Hot Water ◽  
Family House

In the article it was discussed how the energy efficiency of the air-to-water heat pump can change depending on the different ways of the building usage. The author shows that the following factors influence this efficiency: the DHW demand and the demand of the energy for the heating of the building. The article shows that it is very important to take into account the cooperation of both systems, the DHW and the heating. Two models of the SCOP calculations were discussed: in monthly and hourly steps of the calculation. For each model the following assumptions were considered: the different profiles of the domestic hot water demand and the different profiles of the demand for the heating of building.

Experimental Research on Performance of Heat Pump Using Shower Waste Water as Heat Source

2011 ◽  
Vol 480-481 ◽  
pp. 887-892 ◽  
Author(s):  
Han Dong Wang
Keyword(s):  
Waste Water ◽  
Energy Saving ◽  
Heat Pump ◽  
High Energy ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Small Scale ◽  
Stable Operation ◽  
Water Tank ◽  
Water Heater

As we know, there is plenty of waste hot water produced by families’ shower or Sauna and drained directly into the environment. It causes high energy consumption and heat pollution to the environment. In order to recover the heat of shower waste water to save energy, we developed a small scale shower waste water source heat pump (SWWHP) water heater and carried out experiments on it to study its heating performance. Experiments showed that this heat pump water heater system had advantages such as quick starting, compact structure, no need of hot water tank, stable operation and energy saving, etc. It could be used to supply hot water above 40°C for shower or heating, ventilation and air conditioning (HVAC). Measured data showed that during the whole year, when the temperatures of waste water and city water were 20.1～35°C, 20.1～30°C, respectively, it could supply hot water at volumetric flow rate of 2.5～9.6L/min and temperature of 40.1～51.2°C and its heating coefficient of performance (COPh) varied in the range of 3.06～4.81. It could supply enough shower hot water in the whole year in South China and the energy saving efficiency was obvious. Analysis also showed that the COPh was closely relevant to the ratio of temperature differences of waste water and hot water, i.e., ΔTw/ΔTh. The correlation equation of COPh and ΔTw/ΔTh was obtained by method of data regression and it could be used to evaluate the performance of the SWWHP water heater system with error of ±6%.

scholarly journals Optimizing production efficiencies of hot water units using building energy simulations - Trade-off between Legionella pneumophila contamination risk and energy efficiency

2019 ◽  
Vol 111 ◽  
pp. 04053
Author(s):  
Elisa Van Kenhove ◽  
Lien De Backer ◽  
Jelle Laverge
Keyword(s):  
Simulation Model ◽  
Legionella Pneumophila ◽  
Energy Demand ◽  
Energy Use ◽  
Tap Water ◽  
Water System ◽  
High Energy ◽  
Hot Water ◽  
Domestic Hot Water ◽  
Production Efficiencies

The energy needed for domestic hot water represents an important share in the total energy use of well-insulated and airtight buildings. One of the main reasons for this high energy demand is that hot water is produced at temperatures above 60°C to mitigate the risk of contaminating the hot water system with Legionella pneumophila. However, this elevated temperature is not necessary for most domestic hot water applications, and has a negative effect on the efficiency of hot water production units. A simulation model has been developed which proposes an alternative to this constant 60°C by predicting the Legionella pneumophila concentration dynamically throughout the hot water system. Based on this knowledge, a hot water controller is added to the simulation model that sets a lower hot water comfort temperature in combination with heat shocks. In this paper, the simulation model is used to estimate the energy saving potential in a case study building, at the level of the heat production system by reaching higher production efficiencies. Three different production units, namely an electric boiler, heat pump and solar collector have been investigated. The controller is expected to become an alternative for the current, energy intensive, high temperature tap water heating systems.

OPTIMAL HIGH PRESSURE CORRELATION FOR R744 DIRECT EXPANSION SOLAR ASSISTED HEAT PUMP FOR DOMESTIC HOT WATER

2018 ◽  
Author(s):  
Willian Moreira Duarte ◽  
Tiago de Freitas Paulino ◽  
Sabrina Nogueira Rabelo ◽  
Luiz Machado ◽  
Antônio Maia
Keyword(s):  
High Pressure ◽  
Heat Pump ◽  
Hot Water ◽  
Direct Expansion ◽  
Domestic Hot Water

scholarly journals Minimum Number of Experimental Data for the Thermal Characterization of a Hot Water Storage Tank

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4741
Author(s):  
María Gasque ◽  
Federico Ibáñez ◽  
Pablo González-Altozano
Keyword(s):  
Experimental Data ◽  
Water Temperature ◽  
Temperature Profile ◽  
Storage Tank ◽  
Water Storage ◽  
Hot Water ◽  
Experimental Temperature ◽  
Inlet Temperature ◽  
Water Storage Tank ◽  
Minimum Number

This paper demonstrates that it is possible to characterize the water temperature profile and its temporal trend in a hot water storage tank during the thermal charge process, using a minimum number of thermocouples (TC), with minor differences compared to experimental data. Four experimental tests (two types of inlet and two water flow rates) were conducted in a 950 L capacity tank. For each experimental test (with 12 TC), four models were developed using a decreasing number of TC (7, 4, 3 and 2, respectively). The results of the estimation of water temperature obtained with each of the four models were compared with those of a fifth model performed with 12 TC. All models were tested for constant inlet temperature. Very acceptable results were achieved (RMSE between 0.2065 °C and 0.8706 °C in models with 3 TC). The models were also useful to estimate the water temperature profile and the evolution of thermocline thickness even with only 3 TC (RMSE between 0.00247 °C and 0.00292 °C). A comparison with a CFD model was carried out to complete the study with very small differences between both approaches when applied to the estimation of the instantaneous temperature profile. The proposed methodology has proven to be very effective in estimating several of the temperature-based indices commonly employed to evaluate thermal stratification in water storage tanks, with only two or three experimental temperature data measurements. It can also be used as a complementary tool to other techniques such as the validation of numerical simulations or in cases where only a few experimental temperature values are available.

Comparison of Stratification in a Water Tank and a PCM-Water Tank

2007 ◽  
Author(s):  
A. Castell ◽  
C. Sole´ ◽  
M. Medrano ◽  
M. Nogue´s ◽  
L. F. Cabeza
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Temperature Change ◽  
High Energy ◽  
Hot Water ◽  
The Other ◽  
High Energy Density ◽  
Water Tank ◽  
Charging And Discharging Processes ◽  
Change Material

Most of the storage systems available on the market use water as storage medium. Enhancing the storage performance is necessary to increase the performance of most systems. The stratification phenomenon is employed to improve the efficiency of storage tanks. Heat at an intermediate temperature, not high enough to heat up the top layer, can still be used to heat the lower, colder layers. There are a lot of parameters to study the stratification in a water tank such as the Mix Number and the Richardson Number among others. The idea studied here was to use these stratification parameters to compare two tanks with the same dimensions during charging and discharging processes. One of them is a traditional water tank and the other is a PCM-water (a water tank with a Phase Change Material). A PCM is good because it has high energy density if there is a small temperature change, since then the latent heat is much larger than the sensible heat. On the other hand, the temperature change in the top layer of a hot water store with stratification is usually small as it is held as close as possible at or above the temperature for usage. In the system studied the Phase Change Material is placed at the top of the tank, therefore the advantages of the stratification still remain. The aim of this work is to demonstrate that the use of PCM in the upper part of a water tank holds or improves the benefit of the stratification phenomenon.

Simulation of a combined heating, cooling and domestic hot water system based on ground source absorption heat pump

2014 ◽  
Vol 126 ◽  
pp. 113-122 ◽  
Author(s):  
Wei Wu ◽  
Tian You ◽  
Baolong Wang ◽  
Wenxing Shi ◽  
Xianting Li
Keyword(s):  
Heat Pump ◽  
Water System ◽  
Hot Water ◽  
Absorption Heat Pump ◽  
Domestic Hot Water ◽  
Ground Source
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