Analytical modelling and prediction formulas for domestic hot water consumption in residential Finnish apartments

Ferrantelli, Andrea; Ahmed, Kaiser; Pylsy, Petri; Kurnitski, Jarek

doi:10.1016/j.enbuild.2017.03.021

Cited by 46 publications

(28 citation statements)

References 21 publications

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“…where, Φ space , heating power for space (W), Φ T , sum of transmission heat losses through building envelope (external wall, ground, roof, windows, doors, thermal bridges, etc.) (W), Φ I , heat losses caused by infiltration (W), Φ V , heat losses caused by ventilation (W), q v , infiltration rate ( m 3 s ), q 50 , air leakage rate of building envelope ( m 3 h.m 2 ), A env , envelope area (m 2 ), x, factor that based on the building height. The values for single, double, 3-4 storied, 5 or more were 35, 24, 20, and 15, respectively [27].…”

Section: Space Heating Loadmentioning

confidence: 99%

“…However, energy use for DHW heating has kept the same contribution as before, which is considered as the most dominating one in buildings where the space heating (SH) need is low. Energy use for DHW heating seemed unpredictable, which is mainly caused by different DHW usages at occupant and apartment levels [1][2][3]. The detailed hourly DHW usages profile affects the power sizing of a heating system; however, an accurate sizing method does not exist yet for a combined space heating and DHW generation.…”

Section: Introductionmentioning

confidence: 99%

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Modeling an Alternate Operational Ground Source Heat Pump for Combined Space Heating and Domestic Hot Water Power Sizing

2019

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This study developed an alternate operational control system for ground source heat pumps (GSHP), which was applied to determine combined space heating and domestic hot water (DHW) power equations at design temperature. A domestic GSHP with an alternate control system was implemented in a whole building simulation model following the heat deficiency for space heating based on degree minute counting. A simulated GSHP system with 200 L storage tank resulted in 13%–26% power reduction compared to the calculation of the same system with existing European standards, which required separate space heating and DHW power calculation. The periodic operation utilized the thermal mass of the building with the same effect in the case of light and heavy-weight building because of the very short cycle of 30 min. Room temperatures dropped during the DHW heating cycle but kept within comfort range. The developed equations predict the total power as a function of occupancy, peak and average DHW consumption with variations of 0%–2.2% compared to the simulated results. DHW heating added the total power in modern low energy buildings by 21%–41% and 13%–26% at design temperatures of −15 °C and −26 °C, respectively. Internal heat gains reduced the power so that the reduction effect compensated the effect of DHW heating in the case of a house occupied by three people. The equations could be used for power sizing of any heat pump types, which has alternate operation principle and hydronic heating system.

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Section: Space Heating Loadmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling an Alternate Operational Ground Source Heat Pump for Combined Space Heating and Domestic Hot Water Power Sizing

2019

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“…Secondly, and more importantly, we are able to extrapolate and generalize our results to any 10-or 21-type emitter with size included in the studied range, by virtue of the simple interpolation method introduced in [27]. The exact formulas listed in Tables A1 to A4 can be of practical use for qualitative assessments of thermal comfort induced by radiators of 10-or 21-type, with dimensions 0.3m ≤ h ≤ 0.9m and 1.2m ≤ w ≤ 3m and assuming no back wall losses.…”

Section: Discussionmentioning

confidence: 90%

“…We adopt a combined numerical-analytical model that follows the ISO Standard [25], coupled with a simple interpolation method which was introduced in [27] when assessing domestic hot water consumption. We first obtain the surface temperatures of the enclosure numerically, with IDA-ICE, for each heat emitter type and for different sizes; these temperatures are then used as boundary conditions for an analytical calculation of the according operative temperature.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Radiators, Underfloor and Ceiling Heater Towards the Definition of a Reference Ideal Heater for Energy Efficient Buildings

Ferrantelli¹,

Võsa²,

Kurnitski³

2018

Preprint

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Heat emitters constitute the primary devices used in space heating and cover a fundamental role in the energy efficient use of buildings. In the search for an optimized design, heating devices should be compared with a benchmark emitter with maximum heat emission efficiency. However, such an ideal heater still needs to be defined. In this paper we perform an analysis of heat transfer in a European reference room, considering room side effects of thermal radiation and computing the induced operative temperature both analytically and numerically. By means of functional optimization, we analyse trends such as the variation of operative temperature with radiator panel dimensions, finding optimal configurations. In order to make our definitions as general as possible, we address panel radiators, convectors, underfloor (UFH) and ceiling heater. We obtain analytical formulas for the operative temperature induced by panel radiators and identify the 10-type as our ideal radiator, while the UFH provides the best performance overall. Regarding specifically UFH and ceiling heaters, we find optimal sizes that identify the according ideal emitters. The analytical method and quantitative results reported in this paper can be generalized and adopted in most studies concerning the efficiency of different heat emitter types in building enclosures.

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“…Residential buildings consume 16 -50% of the total heat amount, hot water preparation takes a considerable part [1][2][3][4][5][6]. Water heating represents the second largest residential energy use [7].…”

Section: Introductionmentioning

confidence: 99%

Centralized hot tap water systems calculation’s specifics

2018

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Most of the urban housing stock in Latvia as well as in major part of EU cities is apartment multi-storey buildings, most of which have a connection to centralized hot tap water systems. Also, such buildings as dormitories, university campuses, sporting facilities, mostly are connected to the centralized hot tap water systems. The hot tap water systems can have different optional technical solutions, such as recirculation loop, bath towels warmers, etc. All these options affect calculation’s specifics of the systems. The main challenge for designers is to make correct estimation of hydraulic losses, definition of necessary water flow rate and to choose such technical equipment as circulation pumps, balancing valves and circulation water flow. The main parameters directly affecting the sizing of hot tap water system are the number of inhabitants, designed water consumption, consumption uncertainty coefficient, building’s specifics etc. This study is based on the hot water consumption analysis in building were online monitoring system was installed.

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Analytical modelling and prediction formulas for domestic hot water consumption in residential Finnish apartments

Cited by 46 publications

References 21 publications

Modeling an Alternate Operational Ground Source Heat Pump for Combined Space Heating and Domestic Hot Water Power Sizing

Modeling an Alternate Operational Ground Source Heat Pump for Combined Space Heating and Domestic Hot Water Power Sizing

Optimization of Radiators, Underfloor and Ceiling Heater Towards the Definition of a Reference Ideal Heater for Energy Efficient Buildings

Centralized hot tap water systems calculation’s specifics

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