scholarly journals Impact of Boundary Conditions on the Performance Enhancement of Advanced Control Strategies for a Residential Building with a Heat Pump and PV System with Energy Storage

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1413
Author(s):  
Emmanouil Psimopoulos ◽  
Fatemeh Johari ◽  
Chris Bales ◽  
Joakim Widén

Operational control strategies for the heating system of a single-family house with exhaust air heat pump and photovoltaic system and “smart” utilization of energy storage have been developed and evaluated in a simulation study. The main aim and novelty of this study is to evaluate the impact on the benefit of these advanced control strategies in terms of performance (energy use and economic) for a wide range of boundary conditions (country/climate, occupancy and appliance loads). Short-term weather data and historic price data for the same year as well as stochastic occupancy profiles that include the domestic hot water load are used as boundary for a parametric simulation study for the system modeled in detail in TRNSYS 17. Results show that the control using a forecast of dynamic electricity price leads to greater final energy savings than those due to the control using thermal storage for excess PV production in all of the examined locations except Sweden. The impact on self-consumption using thermal storage of heat produced by the heat pump using excess PV production is found to decrease linearly with increasing household electricity for all locations. A reduction in final energy of up to 842 kWh year−1 can be achieved just by the use of these algorithms. The net energy cost for the end-user follows the same trend as for final energy and can result in cost savings up to 175 € year−1 in Germany and Spain due to the use of the advanced control.

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5709
Author(s):  
Zhengjie You ◽  
Michel Zade ◽  
Babu Kumaran Kumaran Nalini ◽  
Peter Tzscheutschler

With the increasing penetration of intermittent renewable energy generation, there is a growing demand to use the inherent flexibility within buildings to absorb renewable related disruptions. Heat pumps play a particularly important role, as they account for a high share of electricity consumption in residential units. The most common way of quantifying the flexibility is by considering the response of the building or the household appliances to external penalty signals. However, this approach neither accounts for the use cases of flexibility trading nor considers its impact on the prosumer comfort, when the heat pump should cover the stochastic domestic hot water (DHW) consumption. Therefore, in this paper, a new approach to quantifying the flexibility potential of residential heat pumps is proposed. This methodology enables the prosumers themselves to generate and submit the operating plan of the heat pump to the system operator and trade the alternative operating plans of the heat pump on the flexibility market. In addition, the impact of the flexibility provision on the prosumer comfort is investigated by calculating the warm water temperature drops in the thermal energy storage given heat demand forecast errors. The results show that the approach with constant capacity reservation in the thermal energy storage provides the best solution, with an average of 2.5 min unsatisfactory time per day and a maximum temperature drop of 2.3∘C.


Author(s):  
Jayson Bursill ◽  
Cynthia A. Cruickshank

Commercially available heat pump water heaters (HPWH) have been used successfully in warm humid climates (southern United States), and recently, have been proven effective in replacing electric water heater technology in cooler climates within Canada. Using an air source HPWH unit within a dwelling can yield electrical coefficients of performance that are indicative of significant energy savings, but can also add an additional load to the space heating system. Current control strategies do not attempt to mitigate the heating load added to the surrounding space, and only consider the water temperature in the tank. This is because, to date, the primary application has been in sub-tropical climates where cooling is frequently beneficial. Starting in 2015, the US Department of Energy is mandating that all electric water heaters have an energy factor (unit of heat applied to hot water per unit of energy applied to the system) greater than 2, which makes technologies that utilize electrical coefficients of performance, such as HPWH technology, mandatory. To ease the inevitable transition to heat pump water heaters in lieu of electric water heaters, modified control strategies that highlight using thermal storage to reduce space heating loads must be implemented. This paper presents a study which was conducted to evaluate the performance of a commercially available HPWH with modified controls. The HPWH is first characterized experimentally under a series of different thermal conditions and draw parameters. The test tank contains a 1500 W electric auxiliary heater that provides on demand heat to the top 0.30 m (1 ft) of the tank, and a wraparound heating coil. An air source heat pump, using R-134A as the refrigerant, draws air from, and returns air to the surrounding space and provides heating to the whole tank through the coil. The tank has been tested using Canadian Standards Association draw profiles to characterize performance under different hot water demands. Electricity consumption and thermal flux is measured for each vertical tank section, and various performance metrics are calculated using energy balances. A TRNSYS model is then calibrated to the experimental data to allow for the flexibility of varying multiple parameters over various climates. Using this calibrated TRNSYS model, an optimal control strategy and tank set-points can be determined for use in cold climates. As expected from previous work, there is a decrease in performance of the heat pump when heating the tank to higher temperatures to facilitate thermal storage, but the benefits from taking advantage of shifting electrical demand (of water heating) to space heating demand can outweigh the loss of performance.


2016 ◽  
Author(s):  
Gabriel Agila ◽  
Guillermo Soriano

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.


Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6282
Author(s):  
Maria Pinamonti ◽  
Alessandro Prada ◽  
Paolo Baggio

The use of photovoltaic (PV) energy in combination with heat pump systems for heating and cooling of residential buildings can lead to renewable energy self-consumption, reducing the energy required from the grid and the carbon footprint of the building uses. However, energy storage technologies and control strategies are essential to enhance the self-consumption level. This paper proposes and analyzes a new control strategy for the operation of a modulating air-source heat pump, based on the actual PV availability. The solar energy surplus is stored as thermal energy by the use of water tanks and the activation of the thermal capacitance of the building. The efficacy of the control strategy is evaluated considering different rule-based strategies, and different boundary conditions. The effect of climate data, building insulation level and thermal inertia are investigated and compared. The results show the efficacy of the proposed strategy to decrease up to 17% the amount of electricity purchased from the grid and to increase the self-consumption by 22%, considering a high-insulated building in Bolzano, Northern Italy. The thermal mass activation is found effective to increase the self-consumption of the system. Nonetheless, the achievable energy reduction depends largely on the building characteristics and the boundary conditions.


2012 ◽  
Vol 238 ◽  
pp. 478-481
Author(s):  
Zhen Qing Wang ◽  
Yan Chen ◽  
Hai Xia Wang

An air source heat pump system (ASHPS) was set up, which provided space heating and cooling, as well as hot water for an office building in Tianjin. Its operating performance in winter was evaluated based on test data. Considering the local abundant solar radiation and the way to provide energy in an office building, a simulation study was carried out on the combsystem of ASHP and flat plate air collector (FPAC). The effects of collector area and its outlet parameters on the heating performance of ASHP were studied, and the favorable operating and matching mode were recommended. The results indicate that ASHPS is a technically viable method in Tianjin in winter, but not economically, and the air-solar combsystem should be taken into account for its massive replacement for conventional energy.


2012 ◽  
Vol 512-515 ◽  
pp. 2904-2907
Author(s):  
Guo Hui Feng ◽  
Kai Liang Huang ◽  
Xin Liu ◽  
Hui Xing Li

The floor heating system of phase change energy storage (FHSPC), performing well in storing and releasing thermal energy, plays a significant role in using solar energy and low-priced nocturnal electrical power for heating. However, due to such problems as ineffective package and insufficient overall integration of phase change material, research of FHSPC has not made progress in practical application. This paper researches thermal storage effect of a new floor heating system of phase change energy storage using solar hot water as the heat source and double layers of capillary network as the heat dissipation end. Differential scanning calorimeter was used to choose capric acid as the main energy storage material. For a steady heating cycle of heating for 8 hours and releasing for 16 hours, acceptable thermal condition is observed in the test room. The new FHSPC could provide long span intermittent heating with little heat loss, therefore the intermittent energy source can be well utilized


2014 ◽  
Vol 541-542 ◽  
pp. 942-948
Author(s):  
Xian Peng Sun ◽  
Zhi Rong Zou ◽  
Yue Zhang

Based on the finite-time thermodynamic theory, an operation optimization, of water source heat pump in the combined solar with a dual heat source heat pump which is applied in a greenhouse heating system, is made. According to the ε-NTU method and entropy theory, heat exchange and balance equations are obtained. The function relationship between COP and the indoor temperature Tn, the ambient temperature Ta, low temperature heat source inlet temperature Tie and high temperature heat source inlet temperature Tic is also obtained. By means of programming, the impact of parameters on the COP and the way of regulating this water source heat pump system are presented in this article. The results show that: when a separate water source heat pump is running, by adjusting the hot water temperature and the match status of each indoor heating system, the energy-saving operation can be realized.


Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5476
Author(s):  
Sławomir Zator ◽  
Waldemar Skomudek

This article presents a case study of a single-family house, whose current energy source is electricity only. Nine years ago, the heat source for the heating system and domestic hot water was an oil boiler, which was changed to an air–water heat pump. Four years ago, when Poland formed the basis of the prosumer market, the first photovoltaic system was established. It was expanded in the following years. In this work are presented the impact of using a heat accumulator on the coefficient of performance of the heat pump, the self-consumption of energy from the photovoltaic system, and the cost of purchasing energy. Comparative calculations were made, with the demand-side management (DSM) active on work days, and on free days (weekends and public holidays) it was not. Attention was paid to the self-consumption factor depending on the algorithms used in an energy meter. The prosumer market in Poland was also described. The calculations described the house as having an annual energy self-consumption from photovoltaic about 6% higher than average values obtained in buildings with heat pumps. Simultaneously, due to energy storage in heat and the load shifting in the multi-zone tariff, the cost of purchasing energy was 47% lower than in a single-zone tariff (without heat storage and load shifting).


Sign in / Sign up

Export Citation Format

Share Document