Potential of residential buildings as thermal energy storage in district heating systems - Results from a pilot test
https://doi.org/10.1016/j.apenergy.2014.07.026

short-term energy storage

also beneficial for HP and RES

variation of electricity prices

special benefits for CHP [2,3]

el. power generation decoupled from heat load

decreases daily variation

conditions for heat generation more favorable

up to few days possible

usually few hours

can increase overall efficiency

periodically overheating and underheating

small indoor T variations

security of energy supply raises

building inertia utilized for thermal storage

intent: generate more heat when favorable

less peak load demand

more base load

better fuel economy

less enviromental impact

heat demand

significant variation within 1 day

problematic conditions for efficient heat generation

variation in DH w/ magnitude of 100 MW during a few hours [1]

on/off boilers

pilot test study

fixed time constant not enough to desribe vriation in indoor T caused by short-term building storage [11]

instead degreehours

storing 0,1 kWh/m^2 will cause rarely dT>|5°C| in heavy building

scope

evaluate magnitude of th. energy storagy capacity while remaining comfort

variation in indoor T only main limiting factor

here: desribed as fcn of limitations for control system expressed in deghrs

can be translated into energy quantity for any building of DH

when energy signature known

independent of building size and location

new method for analyzing how indoor T is affected by utilization of building inertia

signals from outdoor T adjusted in different cycles

supply T radiators set based on outdoor T and control curve

periods of charging and discharging @ diferent times of the day

to seperate variations by test from normal variations

find clear relation between how building TES is controlled and variation of indoor T

building degree hours vs. time constant w/ max. allowed variation of T

closer look at magnitude of heat power per floor area btw. DP, CP, NOP [15]

feedback controller, [11] similar

earlier pilot tests [5-12]

Potential utilization of each building

might be beneficial to have shorter CPs or store heat for a whole day

dT>|0,5°C|

restrictions by cyle II

CP/DP 9h w/ du=+-7°C

not jeopardizing service by heating system

larger du might lead to

residents feeling warm or cold radiators

noise in radiators

small increase in potential

most heating systems shut off when Tout>15°C

3 relations found

Tvar21h~du

Q~du

after step response

rate of change in indoor T decreases w/ time

until more tests available

heavy buildings w/ concrete core tolerate relatively large variations in heat delivery

energy consumption 150 kWh/m^2/a

du = +-7°C

NOP to CP/DP

dQ=10W/m^2

strategies

hot water tanks

quite common

PCMs

require investment

variation of T in DH network

used to compensate time delay

limited

efficiency losses due to higher T in distr.

material fatigue

utilizing building inertia

low cost

great potential