CHAPTER 3: DECARBONIZING SYSTEMS
PART 1: HEATING & COOLING
1: INTRODUCTION
2: SYSTEM CHARACTERISTICS
2.1: CHARACTERISTICS
Many different Heating & Cooling Systems used for both New Buildings & Retrofitting
(het monteren van nieuwe technologieën in een ouder systeem)
- Primary Differences:
> SCALE ENERGY SUPPLY
> HEATING/ COOLING SUPPLY
> QUALITY / TEMPERATURE
> TEMPORAL VARIABILITY
- 4 Examples:
Silkeborg, Denmark:
▪ World’s largest Solar Thermal System
▪ Maximum Power: 110 MW
▪ Annual Heat Produced: 80 000 MWh
▪ Number of Houses connected: 22 000
▪ Supplied Heat Proportion: Max 20%
▪ CO2 Savings Approximately: 15 000 Tonnes / Year
Echo Building, TU Delft, The Netherlands:
▪ Energy Positive Building
▪ High Level of Insulation
▪ 12 000 Solar Panels
▪ Low Temperature Heat supply
▪ Supply Heating & Cooling System: Aquifer Thermal Energy Storage
▪ Balanced Heating & Cooling: 100% Supply covered
Aquifer thermal energy storage (ATES) is the storage and recovery of thermal energy in subsurface aquifers. ATES can heat
and cool buildings. Storage and recovery is achieved by extraction and injection of groundwater using wells. Systems commonly
operate in seasonal modes. Groundwater that is extracted in summer performs cooling by transferring heat from the building to
the water by means of a heat exchanger. The heated groundwater is reinjected into the aquifer, which stores the heated water.
In wintertime, the flow is reversed — heated groundwater is extracted (often fed to a heat pump).
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,Floris, Delft, The Netherlands:
▪ Zero on the Meter Houses, built in 2020 / Zero over the year
▪ Borehole Heat Exchangers: supply heating & cooling
▪ Low Temperature Heating, Underfloor heating / Cooling
▪ Individual Boreholes 150m deep / 4kW heating & cooling
▪ Area of 150 closely (5 à 10m) spaced boreholes
A downhole heat exchanger, (DHE) also called a borehole heat exchanger, (BHE) is a heat exchanger installed inside a vertical
or inclined borehole. It is used to capture or dissipate heat to or from the ground. DHT's are used for geothermal heating,
sometimes with the help of a geothermal heat pump. Downhole heat exchangers, like other use of geothermal energy, have the
potential to significantly contribute to the reduction of CO2 emissions. In northern Europe, DHE are already widely deployed.
Leyweg, The Hague, The Netherlands
▪ First Dutch Urban deep Geothermal project
▪ Supply Heat Grid connected to businesses & homes
▪ Approximately 2000 Homes / 1000 Individual Connections
▪ Heat Supply 75°
▪ Annual Heat Supply 45 TJ
Warmtenet
2.2: MISMATCH SUPPLY AND DEMAND
Daily Basis:
▪ Day / Night Cycle
▪ Solar Energy / Heat Demand
Seasonal Mismatch:
▪ Solar Energy
▪ Wind Energy
➔ How can we use overshoot from the summer into the shortage of the winter?
Thermal Energy Storage (TES) / Heat Storage (HS)
▪ Sensible Thermal Energy Storage (STES) / Sensible Heat Storage (SHS)
Temperature change in solid / liquid medium
▪ Latent Thermal Energy Storage (LTES) / Latent Heat Storage (LHS)
Phase-Changing Capacity
▪ Thermo-Chemical Energy Storage (TCES) / Thermo-Chemical Heat Storage (TCHS)
Fysico-chemical absorption & adsorption processes
= Sorption Thermal Energy Storage
Chemical reactions
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, Sensible heat storage (SHS) is a method of storing thermal energy by heating a substance with a high heat capacity, such as
water or rock, and holding it at an elevated temperature for later use.
Latent heat storage technology (LHS) is a method of storing energy in thermal storage materials (i.e., phase change materials)
that undergo a phase change (i.e., melting, solidifying, vaporizing, or liquefying) when energy is stored and released.
Thermo-chemical heat storage (TCHS) is a type of thermal energy storage system where heat is provided to endothermic
reversible reaction and heat can be extracted when a reversible exothermic reaction occurs.
2.3: OUR SOLAR THERMAL SOURCE
Thermal Radiation
All objects emit EM waves (glow): Hotter objects glow brighter & peak at
shorter wavelengths
Thermal radiation is electromagnetic radiation emitted by the thermal motion of particles in matter.
All matter with a temperature greater than absolute zero emits thermal radiation. The emission of
energy arises from a combination of electronic, molecular, and lattice oscillations in a material.
Spectral Irradiance Curve
The spectral irradiance as a function of photon wavelength
(or energy), denoted by F, is the most common way of
characterising a light source. It gives the power density at
a particular wavelength. The units of spectral irradiance
are in Wm-2µm-1. The Wm-2 term is the power density at
the wavelength λ(µm). Therefore, the m-2 refers to the
surface area of the light emitter and the µm-1 refers to the
wavelength of interest.
Black Body Radiation Law
Black-body radiation is the thermal electromagnetic
radiation within, or surrounding, a body in thermodynamic
equilibrium with its environment, emitted by a black body (an
idealized opaque, non-reflective body). It has a
specific, continuous spectrum of wavelengths, inversely
related to intensity, that depend only on the
body's temperature, which is assumed, for the sake of
calculations and theory, to be uniform and constant.
De wet van Planck, ook wel stralingswet van
Planck genoemd, beschrijft de intensiteitsverdeling van de straling respectievelijk de dichtheidsverdeling van de fotonen, als
functie van de golflengte respectievelijk van de frequentie, van de door een zwarte straler – een ideale stralingsbron – bij een
bepaalde temperatuur uitgestraalde elektromagnetische golven.
de wet van Planck is in feite hetzelfde als de zogenaamde "black body radiation law" (de wet van de straling van een zwart
lichaam). Het verwijst naar een fundamentele natuurkundige beschrijving van hoe een ideaal zwart lichaam (een object dat alle
elektromagnetische straling absorbeert en perfect heruitstraalt) straling uitzendt bij verschillende temperaturen.
De wet van Planck geeft de spectrale intensiteit van de straling (de energie uitgestraald per eenheid van oppervlakte, golflengte
en tijd) als functie van de temperatuur van het zwarte lichaam en de golflengte van de straling. De formule luidt als volgt:
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