This document discusses evaporative cooling technologies for mitigating the urban heat island effect. It reviews literature showing that water features like ponds and fountains can lower air temperatures by around 2.5°C. Small-scale interventions using water spraying were found to have the highest local impact. The study aims to investigate how blue technologies interact with microclimate and urban environments under climate change. It describes a structure with nozzles and shields that reduced air temperatures by 20% through evaporative cooling. Basic HVAC processes are outlined, including sensible heating/cooling and latent humidifying/dehumidifying. Figures show the test location and aluminum support structure used.

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2. INTRODUCTION
• Global warming and Urban Heat Island effect are major stressors on economy, energy, comfort and
health, especially under extreme weather events and where social disparity and energy poverty
thrive.
• The interaction between urban microclimate and electric air conditioning energy consumption has
been investigated not just in hot arid regions, but also in sub-tropical contexts, oceanic climates and
Mediterranean climates with daunting results.
• Science has been moving fast to propose solutions and new criteria for urban planning, boosting a
massive body of sector-specific knowledge and technological progress that demands for periodical
wrap-ups.
• A much less appraised category is that of water-based technologies, namely those that improve the
local climate by means of evaporative processes.

3. LITERATURE REVIEW
• Most papers look into the impacts of open water bodies which, however, are prerogative of few
conurbations in the world. A review on the temperature-mitigating effects of urban wetlands, dating
back to 2015 [20], and another systematic collection [21] on various types of urban blue features
(ponds, lakes or rivers) agree on a mean cooling effect of about 2.5 °C during the warmest months.
• Nevertheless, the meta-analysis by Gunawardena et al. [22] suggest that multiple small-scale
interventions, devised in view of dominant wind patterns and synergistic cooling tend to impact more
than a solitary larger feature.
• Indeed, in a 2017 review paper by Santamouris et al. [23], the authors compared 5 studies on pools,
ponds and open water bodies, three on evaporative wind towers, four on water sprinklers, two on
fountains, four on combinations (both monitored real scale applications and simulation studies
included).Water spraying was found to exert the highest local impact.
• In the same vein, Teleghani and Berardi [24] recently ran high-resolution simulations in ENVI-met to
check the impacts of different materials and features in a main urban square in Toronto under
summer 2015 heat wave conditions. Water ponds and water sprays emerged as especially promising
mitigation strategies (Physiological Equivalent Temperature - PET - reduced by 3.6 °C).

4. AIM OF PROJECT
• the main objective of improving the thermal comfort conditions; typical
applications include pedestrian cool spots, semi-outdoor and temporary spaces.
• our study aims to investigate the impact of complicated interactions between
microclimate, urban built environment, blue technology and climate change

5. THEORY
• To help reduce the adverse effects of UHI and climate change on the urban thermal environment, such as
heat-related mortality [8], the most common adaptation measures are to provide different types of
shade, including trees [9-11] and building structures (eg. [12-14]) to reduce the absorption of direct solar
radiation. Apart from these, spray cooling by water evaporation to reduce the air temperature could be
another efficient way of improving the OTC.
• Gianluco Coccia made a structure made of aluminum that occupies an area of ​​about 24 square meters
and a height of 3 meters. The scientist began installing two pieces of dense fabric (an upper shield used
to mitigate the effect of solar radiation and a four-sided shield used to mitigate the effect of wind
speed). After studying, the scientist found that the height was 2.20 meters, that is, the height of the
nozzles relative to the ground, in the presence of the front shield and the side shield. The reading
indicated a decrease in the average air temperature by 20%, with a noticeable increase in humidity.

6. BASIC HVAC PROCESSES
• The ASHRAE psychrometric chart may be used to solve numerous process problems with moist air. Processes
performed with air can be plotted on the chart for quick visualization, as well as for determining changes in significant
properties such as temperature, humidity ratio, and enthalpy for the process. Some basic air- conditioning processes .
• Sensible heating only (C) or sensible cooling (G) shows a change in dry-bulb temperature with no change in humidity
ratio. For either sensible heat change process, the temperature changes but not the moisture content of the air.
• Humidifying only (A) or dehumidifying only (E) shows a change in humidity ratio with no change in dry- bulb
temperature. For these latent heat processes, the moisture content of the air is changed but not the temperature.
• Cooling and dehumidifying (F) result in a reduction of both the dry-bulb temperature and the humidity ratio. Cooling
coils generally perform this type of process.
• Heating and humidifying (B) result in an increase of both the dry-bulb temperature and the humidity ratio.
• Chemical dehumidifying (D) is a process in which moisture from the air is absorbed or adsorbed by a hygroscopic
material. Generally, the process essentially occurs at constant enthalpy.
• Evaporative cooling only (H) is an adiabatic heat transfer process in which the wet-bulb temperature of the air remains
constant but the dry-bulb temperature drops as the humidity rises.
• Air-Conditioning Processes A Humidifying only B Heating and humidifying C Sensible heating only D Chemical
dehumidifying

7. Fig. 1. Climatic characterization of the case study location. For the observation period, 𝑇ext,av is the average air
temperature, 𝑅𝐻ext,av is the average relative humidity, 𝑊s,av is the
average wind speed, and 𝐼av is the average global solar radiation incident on the horizontal plane.

8. Fig. 3. Aluminum support structure (lengths in cm).
Fig. 2. Outdoor space used for the experimental campaign.

9. Fig. 4. Support structure equipped with the cooling
system, the sensors and part of
the 4-side shielding cloth.