scholarly journals A methodology for designing decentralised energy systems with predictive control for heat pumps and thermal storage

2019 ◽  
Vol 111 ◽  
pp. 06014
Author(s):  
Andrew Lyden ◽  
Paul Tuohy

Decentralised energy systems provide the potential for adding energy system flexibility by separating demand/supply dynamics with demand side management and storage technologies. They also offer an opportunity for implementing technologies which enable sector coupling benefits, for example, heat pumps with controls set to use excess wind power generation. Gaps in this field relating to planning-level modelling tools have previously been identified: thermal characteristic modelling for thermal storage and advanced options for control. This paper sets out a methodology for modelling decentralised energy systems including heat pumps and thermal storage with the aim of assisting planning-level design. The methodology steps consist of: 1) thermal and electrical demand and local resource assessment methods, 2) energy production models for wind turbines, PV panels, fuel generators, heat pumps, and fuel boilers, 3) bi-directional energy flow models for simple electrical storage, hot water tank thermal storage with thermal characteristics, and a grid-connection, 4) predictive control strategy minimising electricity cost using a 24-hour lookahead, and 5) modelling outputs. Contributions to the identified gaps are examined by analysing the sensible thermal storage model with thermal characteristics and the use of the predictive control. Future extensions and applications of the methodology are discussed.

Author(s):  
L. Yang ◽  
M. A. Douglas ◽  
J. Gusdorf ◽  
F. Szadkowski ◽  
E. Limouse ◽  
...  

This paper outlines a demonstration project planned and implemented at the Canadian Centre for Housing Technology (CCHT) in 2006. The CCHT, located on the campus of the National Research Council (NRC) in Ottawa, Ontario, Canada maintains two identical, detached, single-family houses that have the capacity to assess energy and building technologies in side by side comparisons with daily simulated occupancy effects. The paper describes the residential integrated total energy system being installed in one of the homes at the CCHT for this demonstration, consisting of two one-ton ground source heat pumps, an air handler with supplemental/back-up hydronic heating capability, a natural gas fired storage type water tank, an indirect domestic hot water storage tank and a multistage thermostat capable of controlling the system. There is also a description of the bore-field, consisting of three vertical wells arranged to suit a typical suburban landscape. Two of the wells serve the heat pumps; the third well is arranged between the other two to sink the waste heat from a cogeneration unit. The 6 kWe cogeneration unit to be installed in May 2007 is also described. The heat pump system was deliberately sized to satisfy the cooling load in Canada’s heat dominated climate, leaving room in the operation of the system to accept waste heat from the cogeneration unit, either directly or indirectly through recycling the heat through the ground to the heat pumps. This paper presents and discusses preliminary testing results during the fall of 2006 and modeling work of the ground heat exchanger component of the system and therefore sets the stage for performance modeling work that is currently underway at Natural Resources Canada (NRCan).


Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1383
Author(s):  
Abolfazl Rezaei ◽  
Bahador Samadzadegan ◽  
Hadise Rasoulian ◽  
Saeed Ranjbar ◽  
Soroush Samareh Abolhassani ◽  
...  

Designing district-scale energy systems with renewable energy sources is still a challenge, as it involves modeling of multiple loads and many options to combine energy system components. In the current study, two different energy system scenarios for a district in Montreal/Canada are compared to choose the most cost-effective and energy-efficient energy system scenario for the studied area. In the first scenario, a decentral energy system comprised of ground-source heat pumps provides heating and cooling for each building, while, in the second scenario, a district heating and cooling system with a central heat pump is designed. Firstly, heating and cooling demand are calculated in a completely automated process using an Automatic Urban Building Energy Modeling System approach (AUBEM). Then, the Integrated Simulation Environment Language (INSEL) is used to prepare a model for the energy system. The proposed model provides heat pump capacity and the number of required heat pumps (HP), the number of photovoltaic (PV) panels, and AC electricity generation potential using PV. After designing the energy systems, the piping system, heat losses, and temperature distribution of the centralized scenario are calculated using a MATLAB code. Finally, two scenarios are assessed economically using the Levelized Cost of Energy (LCOE) method. The results show that the central scenario’s total HP electricity consumption is 17% lower than that of the decentral systems and requires less heat pump capacity than the decentral scenario. The LCOE of both scenarios varies from 0.04 to 0.07 CAD/kWh, which is cheaper than the electricity cost in Quebec (0.08 CAD/kWh). A comparison between both scenarios shows that the centralized energy system is cost-beneficial for all buildings and, after applying the discounts, the LCOE of this scenario decreases to 0.04 CAD/kWh.


Resources ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 52
Author(s):  
Annette Steingrube ◽  
Keyu Bao ◽  
Stefan Wieland ◽  
Andrés Lalama ◽  
Pithon M. Kabiro ◽  
...  

District heating is seen as an important concept to decarbonize heating systems and meet climate mitigation goals. However, the decision related to where central heating is most viable is dependent on many different aspects, like heating densities or current heating structures. An urban energy simulation platform based on 3D building objects can improve the accuracy of energy demand calculation on building level, but lacks a system perspective. Energy system models help to find economically optimal solutions for entire energy systems, including the optimal amount of centrally supplied heat, but do not usually provide information on building level. Coupling both methods through a novel heating grid disaggregation algorithm, we propose a framework that does three things simultaneously: optimize energy systems that can comprise all demand sectors as well as sector coupling, assess the role of centralized heating in such optimized energy systems, and determine the layouts of supplying district heating grids with a spatial resolution on the street level. The algorithm is tested on two case studies; one, an urban city quarter, and the other, a rural town. In the urban city quarter, district heating is economically feasible in all scenarios. Using heat pumps in addition to CHPs increases the optimal amount of centrally supplied heat. In the rural quarter, central heat pumps guarantee the feasibility of district heating, while standalone CHPs are more expensive than decentral heating technologies.


Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2164
Author(s):  
Vahid Arabzadeh ◽  
Peter D. Lund

Heat demand dominates the final energy use in northern cities. This study examines how changes in heat demand may affect solutions for zero-emission energy systems, energy system flexibility with variable renewable electricity production, and the use of existing energy systems for deep decarbonization. Helsinki city (60 °N) in the year 2050 is used as a case for the analysis. The future district heating demand is estimated considering activity-driven factors such as population increase, raising the ambient temperature, and building energy efficiency improvements. The effect of the heat demand on energy system transition is investigated through two scenarios. The BIO-GAS scenario employs emission-free gas technologies, bio-boilers and heat pumps. The WIND scenario is based on large-scale wind power with power-to-heat conversion, heat pumps, and bio-boilers. The BIO-GAS scenario combined with a low heat demand profile (−12% from 2018 level) yields 16% lower yearly costs compared to a business-as-usual higher heat demand. In the WIND-scenario, improving the lower heat demand in 2050 could save the annual system 6–13% in terms of cost, depending on the scale of wind power.


Author(s):  
Stefan Wischhusen ◽  
Gerhard Schmitz

In this paper, criteria which indicate the usage of transient models and dynamic simulation environments for such energy systems are presented. A complex energy system for heating and cooling of industrial facilities and industrial processes is presented as a reference model. A model of a hot water storage tank is presented, which is optimized for the simulation in whole years, in which a very accurate transient response at much quicker simulation times compared to conventional geometric models can be delivered. The model was validated with measurement data from a large cogeneration plant. In addition, the economical impact of system simulation is emphasized on by an optimization study carried out on a large industrial system. Furthermore, the impact of a transient system model is compared to that of a steady state approach of the same system.


Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3389 ◽  
Author(s):  
Sergio Bruno ◽  
Maria Dicorato ◽  
Massimo La Scala ◽  
Roberto Sbrizzai ◽  
Pio Alessandro Lombardi ◽  
...  

In this this paper, the optimal sizing of electric and thermal storage is applied to the novel definition of a net zero multi energy system (NZEMS). A NZMES is based on producing electricity exclusively from renewable energy sources (RES) and converting it into other energy forms to satisfy multiple energy needs of a community. Due to the intermittent nature of RES, storage resources are needed to increase the self-sufficiency of the system. Possible storage sizing choices are examined considering, on an annual basis, the solution of a predictive control problem aimed at optimizing daily operation. For each day of the year, a predictive control problem is formulated and solved, aimed at minimizing operating costs. Electric, thermal, and (electric) transportation daily curves and expected RES production are assessed by means of a model that includes environmental parameters. Test results, based on the energy model of a small rural village, show expected technical-economic performance of different planning solutions, highlighting how the renewable energy mix influences the choice of both thermal and electric storage, and how self-sufficiency can affect the overall cost of energy.


2014 ◽  
Vol 899 ◽  
pp. 199-204
Author(s):  
Lukáš Skalík ◽  
Otília Lulkovičová

The energy demand of buildings represents in the balance of heat use and heat consumption of energy complex in the Slovak national economy second largest savings potential. Their complex energy demands is the sum of total investment input to ensure thermal protection and annual operational demands of particular energy systems during their lifetime in building. The application of energy systems based on thermal solar systems reduces energy consumption and operating costs of building for support heating and domestic hot water as well as savings of non-renewable fossil fuels. Correctly designed solar energy system depends on many characteristics, i. e. appropriate solar collector area and tank volume, collector tilt and orientation as well as quality of used components. The evaluation of thermal solar system components by calculation software shows how can be the original thermal solar system improved by means of performance. The system performance can be improved of more than 31 % than in given system by changing four thermal solar system parameters such as heat loss coefficient and aperture area of used solar collector, storage tank volume and its height and diameter ratio.


2019 ◽  
Vol 217 ◽  
pp. 01001
Author(s):  
Valery Stennikov ◽  
Evgeny Barakhtenko ◽  
Oleg Voitov

Modern cities and industrial centers boast a developed energy infrastructure including fuel, electric, heating, and cooling systems. The integration of many separate system into a single technological complex can provide new functional capabilities, the application of more advanced technologies for operation, and the establishment of integrated energy systems. Such systems have a multidimensional structure of functional features and properties of development. The control of integrated energy systems with load-controlled consumers represents an urgent and a rather challenging task. The paper is concerned with an approach to short-term control of integrated energy systems with load-controlled consumers. Planning the daily electricity and heat loads is performed for an integrated energy system, including energy storage systems and electric water heaters, electrical shiftable loads of individual consumers as well as power generation by additional electricity and heat sources (PV systems, wind turbines, heat pumps). The optimal daily profiles are obtained based on the initial profiles of electricity and heat loads, photovoltaic generation and optimal profiles of using electricity and heat storage systems and shiftable load. Optimal daily electricity and heat load profiles differ greatly from the initial ones, which provides a reduction in the energy costs for the consumer.


Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 98 ◽  
Author(s):  
Rakesh Sinha ◽  
Birgitte Bak-Jensen ◽  
Jayakrishnan Radhakrishna Pillai ◽  
Hamidreza Zareipour

Active use of heat accumulators in the thermal system has the potential for achieving flexibility in district heating with the power to heat (P2H) units, such as electric boilers (EB) and heat pumps. Thermal storage tanks can decouple demand and generation, enhancing accommodation of sustainable energy sources such as solar and wind. The overview of flexibility, using EB and storage, supported by investigating the nature of thermal demand in a Danish residential area, is presented in this paper. Based on the analysis, curve-fitting tools, such as neural net and similar day method, are trained to estimate the residential thermal demand. Utilizing the estimated demand and hourly market spot price of electricity, the operation of the EB is scheduled for storing and fulfilling demand and minimizing energy cost simultaneously. This demonstrates flexibility and controlling the EB integrated into a multi-energy system framework. Results show that the curve fitting tool is effectively suitable to acknowledge thermal demands of residential area based on the environmental factor as well as user behaviour. The thermal storage has the capability of operating as a flexible load to support P2H system as well as minimize the effect of estimation error in fulfilling actual thermal demand simultaneously.


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