Abating extreme urban heat: Photovoltaic and photosynthetic - PowerPoint PPT Presentation

Abating extreme urban heat: Photovoltaic and photosynthetic hybridization ER Rincon (Mexico City University) M Islas-Espinoza (Mexico State U) A de las Heras (IndyRes)

1995 HEAT WAVE 700 Chicagoans dead Heat is Top US weather killer Europe 2003: ~70 000 dead Tokyo 2018: ~100 dead + concern over 2020 Olympics

1995 heat wave: July 1-17 0.5 Temperature 105 0.45 0.4 95 0.35 90 =32.2 o C 0.3 85 Rainfall 0.25 0.2 75 0.15 0.1 65 18.3 o C= 0.05 55 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 12 12.5 13 13.5 14 14.5 15 15.5 16 16.5 17 Time (half-days) temp (F) precip (in.)

1970s buildings worse: greater mass, poor insulation Humidity, Temperature, low wind speed Over 65, under 5 years old Poverty, living alone Multi-unit housing, top floors, flat roofs Fear of crime: leaving windows closed

PV and CSP to replace fossil Chicago

<17% @ higher COP In the US 17% of electricity use @ 4-5 COP GHG radiative forcing W/m-2

1972 1997

Solution Max gain, min loss of solar irradiance (in UV, Vis and IR) (Trap and use)

Irradiance, global tilt (ASTMG173, 37°) 1.80E+00 𝐽𝑆 1.60E+00 𝐻(𝑢) = 𝐻(𝜇; 𝑢) 𝑒𝜇 = 𝑉𝑊 1.40E+00 1.20E+00 W*m-2*nm-1 1.00E+00 TRAP AND USE 8.00E-01 𝐼 =∫2_ 0^ 24ℎ▒├ 𝐻 ( 𝑢 ) 𝑒𝑢 = Peak H: 20MJ/m 2 /day 6.00E-01 4.00E-01 2.00E-01 0.00E+00 200 700 1200 1700 2200 2700 nm

Goal Given 𝐽𝑆 𝐻 = ∫ 𝐽(𝜇) 𝑒𝜇 , 𝑊𝑗𝑡 obtain A, the part of G absorbed by the hybrid’s subsystems 𝑗 ={PV, PS, Pthermal} and transmitted among them : 𝐽𝑆 𝐵 = 𝐵(𝜇) 𝑗 𝑒𝜇 𝑊𝑗𝑡

How does it lower the temperature: Since heat is Q = 𝑛𝑑 𝑞 ΔT , temperature changes due to the hybrid’s materials are 𝑛𝑑 𝑞 ∆𝑈 = 𝑅 The materials’ emissivity is 𝜁 𝜇 = 𝛽 𝜇 ( Kirchhoff’s law ) and power lost per m 2 is E = 𝜁𝜏𝑈 4 ( Stefan- Boltzmann’s law )

Conceptually, to decrease surface temperature, energy (Vis and IR) is:  Subtracted from the city by radiation absorption and use  Water cooling enhances PV performance  Water after cooling is further heated up by non-imaging thermal solar concentration  *Thermal energy is stored in heated water (removed from city surface and boundary layer)  Latent heat is released by (PS) transpiration  Remaining solar radiation reflected by PV and PS back to space Then, subtracted energy is used to diminish GHG forcings by replacing thermo- and nuclear electricity for AC through:  CO 2 absorption by PS  PV substitution (powering heat pumps and water pumps)  *H 2 O cooling: cool rainwater can be used to cool walls down. * are alternative mechanisms.

Fig. 1. Radiative fluxes of the PV-PS- water hybrid. G is irradiance. 1) PV: opaque/semi-transparent inlaid in transparent glass (50:50 area). 41 o slope also for snow to slide down. 2) Water cooling under PV. 3) PS leaf area; underground irrigation reduces EV, a loss of water to plants. 4) Soil. 5) Concrete. 6a-b) T- stratified water stores thermal energy for wintertime use; summer inflow to cooler 6b is pumped for spray cooling. 6c) Rooftop soil runoff and infiltration overflow. 7) Temporary rain storage pumped upwards to PV underside. 8) Hose. At the end of the cycle, water heated underneath the PV returns to 6b and so warms 6b up.

• (Green) roofs • Parks • Neighbors ’ Where gardens (613711 sq ft=57016 m 2 ) • Urban farms • Boulevards • Parking lots • Walls • Malls Largest convention center in North America • Energy benchmark buildings (≥50,000 sq ft ea or ≥4645 m 2 )

Chicago green roofs (Aug 2010) 1000000 2 223 396, 839 593 y = 0.3097x R² = 0.8138 Vegetated area (Log10(sq ft)) 100000 10000 [VALOR DE X] , [VALOR DE Y] 1000 100 100 1000 10000 100000 1000000 10000000 Total area (Log10(sq ft)) Total area Vegetated area, sq ft or 1639308 and 508130 m 2 17645367 5469466

1.49 USD/W Native to NE IL.

PV interpersed more acceptable to birds Multi-functional plantations more acceptable in Planting Priority Areas (highly urbanized) Goodnesses of hybrids

PS contribution 1. Absorb photons 2. Absorb C-CO 2 3. Transpire: cooling via latent heat release 4. Cool down PV underside 5. Shade (decrease mean T)

1. Absorb photons Photon flux density (PFD, µmol*m -2 *s -1 ) (from irradiance G) Photosynthetic PFD (µmol*m -2 *s -1 ) (PAR=Vis) 4 photons + 2H 2 O  4 H + + 4e - + O 2 (light dependent phase) For a 700 nm photon, E(eV)=hc/ λ (µm)=1.2398/0.7µm=1.771 eV (1 eV = 1.602(10 -19 ) J) 48 photons + 6CO 2 + 12H 2 O  C 6 H 12 O 6 + 6O 2 + 6H 2 O (light (in)dependent phases) where C 6 H 12 O 6 is one glucose molecule

2. Absorb CO 2 48 photons + 6CO 2 + 12H 2 O  C 6 H 12 O 6 + 6O 2 + 6H 2 O C-CO 2 /kg standing biomass C-CO 2 /kg NEP

C 6 H 12 O 6 : 16.3 kJ/g calorific content Human brain tissue requirement : 5.6 mg glucose/100g per 60 s Mol glucose/mol photons * mol photons*W -1 m -2 => mol glucose*W -1 m -2 feeds how many human brains for one second?

3. Transpiration (loss of water vapor by plants) Energy use by transpiration is 0=(G+ 𝑇 )−( 𝑠 G, 𝑇 − 𝑆 )± 𝐼 ± 𝑚𝐹 + 𝐵 with G total solar radiation, 𝑇 the IR from soil and buildings, 𝑠 G, 𝑇 radiation reflected from leaves, 𝑆 radiation reradiated from leaves (‘additive radiation’), 𝐼 sensible heat exchange with the environment by convection and advection, 𝑚𝐹 latent heat lost in transpiration or gained in dew or frost formation, and 𝐵 energy used in metabolic processes (e.g. photosynthesis 2-3% of the total) In addition to transipiration, there is energy used in evaporating dew or rainfall drops (latent heat).

The hybrid • PV and PS mutually regulate their T • Water regulates PV and PS T • PV protects PS underneath from acid rain and keeps PS in High Efficiency State rather than Photoprotected State UNLIKE OTHER ENERGY SOURCES: • Produces O 2 (whereas combustion decreases O 2 ) • Produces energy (for living beings and machines) • CLEANS! (CO 2 , C- and non-C particles, waste heat) • Can be carbon-negative • Keeps CLEAN water inside the city rather than SOILING and evacuating it • Sustainability accountability can be done at the building level (I clean my act AND sweep in front of my door) • Aesthetic value • Mid-term cost reduction

Is this also useful to curb global warming? SAME time PATTERN AS MONTHLY Mauna Loa CO 2 ppm PROBABLY SO (space-time dependence):

Thanks! Let’s retrofit locally! rinconsolar@hotmail.com ICUC10, NYC, Aug 2018