Flow models of perforated manifolds and plates for the design of a large thermal storage tank for district heating with minimal maldistribution and thermocline growth

Pilotelli, Mariagrazia; Grassi, Benedetta; Lezzi, Adriano Maria; Beretta, Gian Paolo

doi:10.1016/j.apenergy.2022.119436

Cited by 8 publications

(5 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, to decrease the utilisation of natural gas boilers and increase the use of waste-to-energy plant, thermal energy storages have been installed in the city, the first with a capacity of 5000 m 3 of water, the other two with a capacity of 2200 m 3 each. They feature an innovative water supply system, that was designed by A2A Calore & Servizi in collaboration with the University of Brescia [22]. A first performance analysis is reported in the study of Pilotelli et al [23].…”

Section: The A2a North Power Plant In Bresciamentioning

confidence: 99%

Design of a 5th Generation District Heating Substation Prototype for a Real Case Study

Martinazzoli

Pasinelli²,

Lezzi

et al. 2023

Sustainability

View full text Add to dashboard Cite

The evolution of district heating networks is moving toward low temperatures in heat distribution with so called 4th generation networks. However, the lowest heat transfer fluid temperatures in district heating are achieved through ultra-low temperature networks, referred to as 5th generation district heating networks (5GDHNs). Low temperatures in heat distribution results in an extremely different configuration of 5GDHN compared to traditional district heating network, especially in the grid substation due to the inability to directly couple the grid with the buildings. This paper presents a detailed design of a 5th generation substation prototype, which is carried out to verify the proper operation and monitor the performance of this type of substation in a real case study. The prototype is fed by low-temperature waste heat, currently dissipated through evaporative towers, and will be built in the city of Brescia, Italy. The layout of the substation prototype, consisting of a bidirectional pumping system, a reversible water-to-water heat pump, an inertial thermal energy storage and a heat exchanger, is presented. An analysis is performed to figure out which refrigerant offers the best performance of the heat pump. In addition, fixed the refrigerant, the performance of the grid connected heat pump is found to be increased from 29.5% to 55.5% for both heating and cooling compared with a stand-alone air-to-water heat pump solution. Finally, the process flow diagram and the piping and instrumentation diagram of the substation are presented and commented.

show abstract

Section: The A2a North Power Plant In Bresciamentioning

confidence: 99%

Design of a 5th Generation District Heating Substation Prototype for a Real Case Study

Martinazzoli

Pasinelli²,

Lezzi

et al. 2023

Sustainability

View full text Add to dashboard Cite

show abstract

“…The novelty of the Lamarmora injection system, co-designed by A2A Calore & Servizi and the University of Brescia, lies in the perforation of the manifold, which was designed to minimize radial velocity non-uniformity in the circumferential direction, and in the presence of a flow-straightening device consisting of a perforated plate above the lower manifold and one below the upper manifold. The system is described in detail by Pilotelli et al [14]. The Lamarmora TES has a total capacity of 5500 m 3 provided by a single tank of shape ratio L/D=0.94.…”

Section: Tes Featuresmentioning

confidence: 99%

“…In this paper, a comparison is made between a newer TES, equipped with an innovative injection and extraction system comprising toroidal manifolds and flow-straightening devices, and two older TESs, each composed of two twin tanks without flow-straightening devices and with different toroidal manifold characteristics. The TES tank with the innovative injection system, co-designed by A2A Calore & Servizi and the University of Brescia [14], was installed in the DH network of Brescia and went into operation in January 2020. The system adopted for this tank is the first of its kind, with optimized and experimentally validated perforation characteristics of both the toroidal manifold and the flowstraightening device.…”

Section: Introductionmentioning

confidence: 99%

Comparative Analysis of Thermal Energy Storage Performance in District Heating Networks: Evaluating the Impact of Different Injection Systems

Martinazzoli,

Grassi,

Pasinelli

et al. 2023

IJHT

View full text Add to dashboard Cite

A primary objective of contemporary district heating (DH) networks is to minimize the use of primary energy, especially fossil fuels, for meeting the heating demands of grid customers. In this context, thermal energy storages (TESs) serve as crucial devices, facilitating the decoupling of grid demand from heat generation. This study presents an experimental comparison of three large-scale TESs, each employing distinct injection and extraction systems. The performance of these were examined based on data collected over a consistent two-month operational period, enabling a quantitative comparison. The TESs under scrutiny, located in the DH networks of Milan and Brescia in Northern Italy, each have a capacity of a few thousand cubic meters of water and differ in their injection system and shape ratio. Notably, the evolution and thickness of the thermocline and the percentage of energy waste were examined to discern the impact of the injection system, specifically the presence of a flow-straightening device, and the shape ratio on the performance of the TES systems. These characteristics were found to significantly influence energy waste in heat storage, which ranged from 1.56% to 6.50% of the total stored energy, depending on the specific TES tank under consideration.

show abstract

“…Changing the installation position, shape, and structure of the diffuser will have a significant impact on its performance [3][4][5]. Therefore, many scholars have studied the influencing factors of diffusers in different directions and optimized the design scheme.…”

Section: Introductionmentioning

confidence: 99%

Evaluation Method and Analysis on Performance of Diffuser in Heat Storage Tank

Cao,

Yu,

Liu

et al. 2024

Energies

View full text Add to dashboard Cite

The diffuser is a critical component in a heat storage tank, and its structure has an important influence on the thermal performance of the heat storage tank. At present, research on the structure of diffusers often focuses on the change of one single parameter, which results in the need for a comprehensive structure analysis of diffusers in heat storage tanks. This paper comprehensively considers the inlet diameter, hole distance, and hole diameter of the diffuser and the inlet conditions of the heat storage tank. Then, a new evaluation index, namely the non-uniformity coefficient of the diffuser, is proposed. The experiments verify the accuracy of numerical calculation, and the related empirical formula is summarized finally. The results show that the diffuser with a small non-uniformity coefficient can achieve thin temperature stratification and higher exergy efficiency. In other words, the non-uniformity coefficient is in good agreement with temperature stratification and the exergy efficiency of the heat storage tank. When the flow rate of the inlet device is 0.5 m/s, the exergy efficiency increases by nearly 30 percentage points and the non-uniformity coefficient of the No. 4 diffuser is 3.39%. In contrast, that of the No. 8 diffuser is 75.17%. This evaluation index is suitable for different diffuser types with high accuracy. It provides the theoretical and experimental basis for the structural design and selection of diffusers for heat storage tanks.

show abstract

Flow models of perforated manifolds and plates for the design of a large thermal storage tank for district heating with minimal maldistribution and thermocline growth

Cited by 8 publications

References 32 publications

Design of a 5th Generation District Heating Substation Prototype for a Real Case Study

Design of a 5th Generation District Heating Substation Prototype for a Real Case Study

Comparative Analysis of Thermal Energy Storage Performance in District Heating Networks: Evaluating the Impact of Different Injection Systems

Evaluation Method and Analysis on Performance of Diffuser in Heat Storage Tank

Contact Info

Product

Resources

About