Analysis of monthly and daily profiles of DHW use in apartment blocks in Norway

Ivanko, Dmytro; Walnum, Harald Taxt; Sørensen, Åse Lekang; Nord, Nataša

doi:10.1051/e3sconf/202017212002

Cited by 4 publications

(3 citation statements)

References 12 publications

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“…The daily values show an increased CHW during the morning, from about 06:00 during the weekdays and about during 08:00 weekends. There is a morning and afternoon peak, as also observed in other apartment buildings [24], but also the DHW uses during other daytime hours are quite high. An explanation for this could be that residents with small children or elderly are overrepresented, which is reasonable given that the apartments have two bedrooms only.…”

Section: Dhw Energy Need and Supplied Energysupporting

confidence: 54%

Energy flexibility potential of domestic hot water systems in apartment buildings

et al. 2021

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Domestic Hot Water (DHW) storage tanks are identified as a main source of flexible energy use in buildings. As a basis for energy management in apartment buildings, this paper describes the aggregated DHW use in a case building, and analyses the potential for DHW energy flexibility by simulating different control options. The case study for the work is an apartment building in Oslo with 56 apartments and a shared DHW system. Energy measurements are available for consumed hot water, hot water circulation, and energy supplied to the DHW tanks. The measurements are presented with minute, hourly and daily values. Aggregated daily energy use for the consumed hot water is in average 362 kWh, while the energy supplied is 555 kWh. The potential for energy flexibility is analysed for a base case and for four different rule-based control options: Power limitation, Spot price savings, Flexibility sale and Solar energy. Economic consequences of the control options are compared. With the Norwegian tariff structure, maximum hourly power use has the main impact on the cost. Control systems that aim to reduce the maximum power use may be combined with spot price savings or to offer end-user flexibility services to the grid.

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Section: Dhw Energy Need and Supplied Energysupporting

confidence: 54%

Energy flexibility potential of domestic hot water systems in apartment buildings

et al. 2021

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“…Both heating demand and electricity prices are influenced by the weather with higher energy prices often coinciding with higher heating demand such as in sustained cold periods. Real DHW profiles for Norwegian apartment buildings have been found to be less volatile than the standardised profile [60,61], which could result in smaller cost savings. However, the measured profiles also showed variation seasonally and between weekdays and weekends, which could offer other opportunities for load shifting.…”

Section: Discussionmentioning

confidence: 99%

Analysing the Economic Viability of Implicit Demand Response Control of Thermal Energy Storage in Hot Water Tanks

Gibbons

Javed

2022

Energies

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Demand-responsive control of electrically heated hot water storage tanks (HWSTs) is one solution, already present in the building stock, to stabilise volatile energy networks and markets. This has been put into sharp focus with the current energy crisis in Europe due to reduced access to natural gas. Furthermore, increasing proportions of intermittent renewable energy will likely add to this volatility. However, the adoption of demand response (DR) by consumers is highly dependent on the economic benefit. This study assesses the economic potential of DR of centralised HWSTs through both an analysis of spot price data and an optimisation algorithm approximating DR control. The methods are applied to a case study apartment building in Norway using current pricing models and examine the effect of the demand profile, electricity prices, heating power and storage capacity on energy cost and energy flexibility. Unit cost savings from DR are closely linked to the variation in unit energy price during the optimisation period. Increasing the storage capacity or the heating power increases the flexibility with a diminishing rate of return. However, increasing storage capacity does not result in cost savings as additional heat losses are greater than the saving from shifting demand, except for during highly volatile electricity price periods. Changing the minimum setpoint temperature improves the cost curve as a greater thermal storage capacity can be achieved without increasing heat loss. Systems utilising a smaller heating power are more economical due to the dominant role of the monthly price related to the peak energy demand of the system.

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“…The inaccuracy of profiles presented in the standards is one of the reasons for incorrect tank sizing. In the study [8], the DHW heat use profiles obtained from measurements in Norwegian residential buildings were compared with profiles presented in national and international standards. The comparison showed that the reference profiles in standards are not accurate enough.…”

Section: Introductionmentioning

confidence: 99%

DHW tank sizing considering dynamic energy prices

et al. 2021

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Due to the rapid development of the building stock in Norway, the energy use in this segment is drastically increasing. Therefore, improving the energy performance of buildings becoming an urgent problem. Among technical systems in buildings, domestic hot water (DHW) systems have still significant untapped potential for energy saving. Storage tanks enable us to change DHW demand in buildings in a more energy-efficient and cost-effective way. However, to achieve this effect, the proper sizing and operation of the storage tanks are required. The aim of this study was to define a method for the DHW tank size optimization considering dynamic electricity prices and to assess how different electricity pricing methods would influence the DHW tank size. A dynamic discretized model of the DHW tank was used as a DHW tank model. Dynamic optimization was implemented as the optimization method to find the optimal tank charging rate based on the different pricing methods. Two pricing methods were considered in this study: 1) the current method with the fixed grid fee and 2) the power extraction method with the pricing of the maximum power extraction. The results showed that the electricity pricing pattern had significant impact on the DHW charging heating rate. In the case of the extraction fee pricing method, the charging rate was more stable over the day than in the case of the fixed grid fee. This stable charging rate gave stable DHW tank temperature over the day and the highest decrease in the total cost. A general conclusion was that the extraction grid fee pricing method would promote for stable charging over the day.

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Analysis of monthly and daily profiles of DHW use in apartment blocks in Norway

Cited by 4 publications

References 12 publications

Energy flexibility potential of domestic hot water systems in apartment buildings

Energy flexibility potential of domestic hot water systems in apartment buildings

Analysing the Economic Viability of Implicit Demand Response Control of Thermal Energy Storage in Hot Water Tanks

DHW tank sizing considering dynamic energy prices

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