MAR: Regenerative design – Comfort, Energy, Water
Chapter 3: Decarbonizing Systems
Part 1: Heating & Cooling
0. INTRODUCTION
Steps toward Zero-Energy and Zero-Carbon Design:
• Step 0 (Research): Study the local circumstances.
• Step 1 (Reduce): Reduce the demand using passive, smart bioclimatic design.
• Step 2 (Reuse): Use residual flows such as wastewater, waste material, or waste heat/cold in
closed or connected cycles.
• Step 3 (Produce): Generate renewable energy.
1. SYSTEM CHARACTERISTICS
Key Characteristics of Energy Supply:
• Scale: Large (energy for many users requiring distribution) vs. small (individual local users).
E.g. infrastructure for a city vs. a sole building
• Supply Type: Output is only heating, only cooling, or combined heating & cooling.
• Quality (temperature):
o High quality: High temperature, more flexible, energy-dense, lower transport costs.
o Low quality: Lower temperature, more easily available (abundant) in the environment,
lower heat losses.
• Temporal variability: Systems can be stable or varying. This is the nature of energy demand or
supply over time.
Case Studies:
• Example 1: Silkeborg, Denmark: The world's largest solar thermal system with a maximum power
of 110 MW. It produces 80,000 MWh (Megawatt-hour) annually for 22,000 houses, covering up
to 20% of the heat demand and saving 15,000 tonnes of CO2 per year.
• Example 2: Echo Building, TU Delft (Netherlands): An energy-positive building with 1,200 solar
panels and high insulation. It uses ATES (aquifer thermal energy storage) for balanced heating
and cooling, covering 100% of the supply with low-temperature heat.
• Example 3: Floris, Delft (Netherlands): Zero-on-the-meter houses (2020). They use individual
borehole heat exchangers (~150m deep, ~4kW heating and cooling and ~150 boreholes) for low-
temperature underfloor heating and cooling.
NOM houses: houses that generate as much energy as it consumes over the course of a year. In
Summer you put the surplus energy on the net, in winter you take from the net but the amounts
are the same.
• Example 4: Leyweg, The Hague (Netherlands): First urban deep geothermal project (from 2022)
supplying a heat grid for ~2000 houses and ~1000 individual connections (businesses),
supplying 75°C of heat, providing 75% of the annual heat supply (45TJ).
1
,Conclusion: many different heating and cooling systems are used for both new buildings and retrofitting.
Supply and Demand Mismatch:
• Daily Mismatch: The day/night cycle affects solar energy availability versus the actual heat
demand during the day and night.
Graph: A lot of surplus energy from during the day that exceeds the immediate demand. The
solution would be heat storage; capturing that surplus energy during the day and shifting it to the
night or morning to meet the demand when production is low.
• Seasonal Mismatch: High solar/wind energy production in summer versus high demand in winter.
Dunkelflaute: Periods of several days/weeks with no sun and no wind ("grey days"), this happens
in the winter when the demand is highest. The solution requires long term storage rather than
short term batteries as before.
➔ How can we use the overshoot from the summer into the shortage in winter?
Thermal Energy Storage (TES) or heat storage (HS) Types:
• Sensible (STES or SHS): Storage via changing the temperature in solid or liquid mediums (e.g.,
water or rocks).
• Latent (LTES or LHS): Storage using phase-changing materials (PCM) or changing the state of the
material. (E.g. from solid to liquid).
• Thermo-chemical (TCES or TCHs): Storage via physico-chemical absorption/adsorption processes
(Sorption). It stores energy through reversible chemical reactions (break and recombine chemical
bonds releasing heat again) or sorption processes.
Our Solar Thermal Source
The solar source:
• Electromagnetic Spectrum: Solar radiation includes ultraviolet (UV), visible light, and infrared (IR).
The sun acts as a thermal source because it emits energy across the Electromagnetic (EM)
Spectrum based on its temperature.
• Thermal radiation: Every object emits electromagnetic (EM) waves. Even if you can't see it,
everything is "glowing" with energy. The hotter an object becomes, the more energy it radiates,
making it "brighter." As temperature increases, the radiation shifts toward shorter wavelengths.
• Spectral irradiance curve: how sun’s power is distributed across different wavelengths of light.
Visible light contains the highest energy density (thermal collectors absorb this to reach high
temperatures). Infrared is pure heat radiation, thermal collectors can capture almost all of it.
Both are on the shorter wavelengths side.
Irridiance: intensity of the sun at a specific moment or instantaneous power.
• Black Body Radiation law: the specific way an object emits energy based on its temperature only.
So the temperature of an object determines the intensity and wavelength of the light it emits.
Black body radiation is simpelweg de straling (licht of warmte) die elk voorwerp uitzendt omdat het een
bepaalde temperatuur heeft.
2
, The Sun (at ~5500°C) peaks in the visible radiation spectrum (rainbow colors) and its intensity at 64
MW/m².
Graph: ultraviolet radiation is high energy radiation emitted by very hot sources (10000 K) and appear
blue. Radiation from the sun is at 5500K and is visible radiation, appears white. Infrared radiation at
2000 K is heat radiation that is emitted by cooler objects like humans and buildings, they appear orange,
red, black, grey...
• Solar irradiance at earth: using the Sun's physical dimensions and power density to determine
how much energy actually reaches our planet's outer atmosphere.
• Effect on the atmosphere: Clear sky solar irradiance is ~1000 W/m². Factors like the Sun's zenith
angle and Air Mass (AM) affect the annual irradiation (e.g., ~1000 kWh/m² in the Netherlands vs.
~2500 kWh/m² in Egypt).
Top of the atmosphere is the sunlight before it hits our air (matches 5500K Blackbody spectrum.)
Sea level radiation is the sunlight that actually makes it through.
• Global irradiance to a solar panel: direct, diffuse and ground diffuse irradiance.
Sun’s zenith angle (θ) affects the intensity of solar radiation reaching the ground.
Extra distance through atmosphere: longer path for the sunrays to travel, more absorption and scattering
of energy
Air Mass: factor that quantifies the length of that path (no unit)
Air Mass (AM) = 1/cos(θ)
• Annual irradiance
Irradiance is instantaneous power (W/m²) → while irradiation is energy over time (kWh/m²).
Irradiance is the instant power (intensity at one moment) of solar radiation per unit area, it is measured
in W/m2 (it is instantaneous, therefore no time dimension in the units).
Irradiation is the quantity (how much) of solar energy per unit area, measured in Wh/m2/time (day or
year or so; time dimension here is relevant).
3
Chapter 3: Decarbonizing Systems
Part 1: Heating & Cooling
0. INTRODUCTION
Steps toward Zero-Energy and Zero-Carbon Design:
• Step 0 (Research): Study the local circumstances.
• Step 1 (Reduce): Reduce the demand using passive, smart bioclimatic design.
• Step 2 (Reuse): Use residual flows such as wastewater, waste material, or waste heat/cold in
closed or connected cycles.
• Step 3 (Produce): Generate renewable energy.
1. SYSTEM CHARACTERISTICS
Key Characteristics of Energy Supply:
• Scale: Large (energy for many users requiring distribution) vs. small (individual local users).
E.g. infrastructure for a city vs. a sole building
• Supply Type: Output is only heating, only cooling, or combined heating & cooling.
• Quality (temperature):
o High quality: High temperature, more flexible, energy-dense, lower transport costs.
o Low quality: Lower temperature, more easily available (abundant) in the environment,
lower heat losses.
• Temporal variability: Systems can be stable or varying. This is the nature of energy demand or
supply over time.
Case Studies:
• Example 1: Silkeborg, Denmark: The world's largest solar thermal system with a maximum power
of 110 MW. It produces 80,000 MWh (Megawatt-hour) annually for 22,000 houses, covering up
to 20% of the heat demand and saving 15,000 tonnes of CO2 per year.
• Example 2: Echo Building, TU Delft (Netherlands): An energy-positive building with 1,200 solar
panels and high insulation. It uses ATES (aquifer thermal energy storage) for balanced heating
and cooling, covering 100% of the supply with low-temperature heat.
• Example 3: Floris, Delft (Netherlands): Zero-on-the-meter houses (2020). They use individual
borehole heat exchangers (~150m deep, ~4kW heating and cooling and ~150 boreholes) for low-
temperature underfloor heating and cooling.
NOM houses: houses that generate as much energy as it consumes over the course of a year. In
Summer you put the surplus energy on the net, in winter you take from the net but the amounts
are the same.
• Example 4: Leyweg, The Hague (Netherlands): First urban deep geothermal project (from 2022)
supplying a heat grid for ~2000 houses and ~1000 individual connections (businesses),
supplying 75°C of heat, providing 75% of the annual heat supply (45TJ).
1
,Conclusion: many different heating and cooling systems are used for both new buildings and retrofitting.
Supply and Demand Mismatch:
• Daily Mismatch: The day/night cycle affects solar energy availability versus the actual heat
demand during the day and night.
Graph: A lot of surplus energy from during the day that exceeds the immediate demand. The
solution would be heat storage; capturing that surplus energy during the day and shifting it to the
night or morning to meet the demand when production is low.
• Seasonal Mismatch: High solar/wind energy production in summer versus high demand in winter.
Dunkelflaute: Periods of several days/weeks with no sun and no wind ("grey days"), this happens
in the winter when the demand is highest. The solution requires long term storage rather than
short term batteries as before.
➔ How can we use the overshoot from the summer into the shortage in winter?
Thermal Energy Storage (TES) or heat storage (HS) Types:
• Sensible (STES or SHS): Storage via changing the temperature in solid or liquid mediums (e.g.,
water or rocks).
• Latent (LTES or LHS): Storage using phase-changing materials (PCM) or changing the state of the
material. (E.g. from solid to liquid).
• Thermo-chemical (TCES or TCHs): Storage via physico-chemical absorption/adsorption processes
(Sorption). It stores energy through reversible chemical reactions (break and recombine chemical
bonds releasing heat again) or sorption processes.
Our Solar Thermal Source
The solar source:
• Electromagnetic Spectrum: Solar radiation includes ultraviolet (UV), visible light, and infrared (IR).
The sun acts as a thermal source because it emits energy across the Electromagnetic (EM)
Spectrum based on its temperature.
• Thermal radiation: Every object emits electromagnetic (EM) waves. Even if you can't see it,
everything is "glowing" with energy. The hotter an object becomes, the more energy it radiates,
making it "brighter." As temperature increases, the radiation shifts toward shorter wavelengths.
• Spectral irradiance curve: how sun’s power is distributed across different wavelengths of light.
Visible light contains the highest energy density (thermal collectors absorb this to reach high
temperatures). Infrared is pure heat radiation, thermal collectors can capture almost all of it.
Both are on the shorter wavelengths side.
Irridiance: intensity of the sun at a specific moment or instantaneous power.
• Black Body Radiation law: the specific way an object emits energy based on its temperature only.
So the temperature of an object determines the intensity and wavelength of the light it emits.
Black body radiation is simpelweg de straling (licht of warmte) die elk voorwerp uitzendt omdat het een
bepaalde temperatuur heeft.
2
, The Sun (at ~5500°C) peaks in the visible radiation spectrum (rainbow colors) and its intensity at 64
MW/m².
Graph: ultraviolet radiation is high energy radiation emitted by very hot sources (10000 K) and appear
blue. Radiation from the sun is at 5500K and is visible radiation, appears white. Infrared radiation at
2000 K is heat radiation that is emitted by cooler objects like humans and buildings, they appear orange,
red, black, grey...
• Solar irradiance at earth: using the Sun's physical dimensions and power density to determine
how much energy actually reaches our planet's outer atmosphere.
• Effect on the atmosphere: Clear sky solar irradiance is ~1000 W/m². Factors like the Sun's zenith
angle and Air Mass (AM) affect the annual irradiation (e.g., ~1000 kWh/m² in the Netherlands vs.
~2500 kWh/m² in Egypt).
Top of the atmosphere is the sunlight before it hits our air (matches 5500K Blackbody spectrum.)
Sea level radiation is the sunlight that actually makes it through.
• Global irradiance to a solar panel: direct, diffuse and ground diffuse irradiance.
Sun’s zenith angle (θ) affects the intensity of solar radiation reaching the ground.
Extra distance through atmosphere: longer path for the sunrays to travel, more absorption and scattering
of energy
Air Mass: factor that quantifies the length of that path (no unit)
Air Mass (AM) = 1/cos(θ)
• Annual irradiance
Irradiance is instantaneous power (W/m²) → while irradiation is energy over time (kWh/m²).
Irradiance is the instant power (intensity at one moment) of solar radiation per unit area, it is measured
in W/m2 (it is instantaneous, therefore no time dimension in the units).
Irradiation is the quantity (how much) of solar energy per unit area, measured in Wh/m2/time (day or
year or so; time dimension here is relevant).
3
