ASHRAE Journal - January 2023 - 35

FEATURE
PHOTO 1. A hut in an off-grid region of the
Peruvian Andes, where each year at least 600
children die due to the freezing weather and a
lack of insulation and heating sources.
Background
The CAT system addresses a worldwide signifi cant
challenge: areas exist where people live off-grid without
access to any sources of thermal energy, and thousands
die every year because they lack access to enough
thermal energy to heat themselves, their homes and
their animals during winter. Further, in some of these
areas, people do not and cannot have access to energy
generated from windmills or PV systems. Some of
those areas are in the Peruvian Andes, where many
people live 4000 m (13,123 ft) or higher than sea level.
In Perú, at least 600 children die each year1,2 because
of exposure to low temperatures during the winter.
Temperatures can fl uctuate between −20°C and -10°C
(-4°F and 14°F) on the coldest nights and between −5°C
and 0°C (23°F and 32°F) on nights that are less cold.
The way local Peruvian governments have tried
to help for many years is by giving people blankets.
However, when outside temperatures reach the lows
mentioned above, inside-the-home temperatures
quickly match the temperatures outside, especially
at night. (See " Why Do Inside Temperatures Match
Outside Temperatures? " on page 38.) These houses lack
proper thermal insulation in their walls, ceilings and
fl oors and also lack internal sources of thermal energy.
These factors debilitate children and the elderly
quickly. Low temperatures cause respiratory illnesses
among children, contributing to childhood deaths.
Even in developed nations, people die due to freezing
weather. In the U.S., for example, deaths caused by
cold temperatures have been documented for decades3
and will likely worsen in the coming decades due to
extreme temperatures driven by climate change.
What happens when you surround a person with a
blanket is similar to the physics of the fl ow of thermal
energy from inside to outside a room. There are two
temperatures, the one inside and the one outside the
person, and the thermal energy that fl ows from the person
to the surrounding environment is proportional to
the ratio of the differential temperatures to the thermal
resistance of the blanket. No matter what, after a certain
point , if no thermal energy is provided to the person or
the room they are in, there is a moment in which the
temperature of the person will start decreasing. If that
loss of thermal energy is not compensated for, the person
will be subject to adverse health effects. This is the
reason so many children die during the winter in these
areas. We believe that this is an engineering challenge,
and it is the duty of engineers to fi nd a solution.
Given these challenges, in 2018 we began
investigating how thermal energy could be collected,
stored and transferred to these houses. We were
inspired to create a sustainable home heating system
based on low-cost simple and available materials
versus more expensive technical components ideal
for using the good radiation of the Andean region
(700 W/m2 [65 W/ft2]) and storing the thermal energy
in rocks. This system can be built with inexpensive
materials, used in signifi cantly isolated areas and be
constructed and assembled on-site.
J A N U A RY 2 0 2 3 ashrae.o rg ASHRAE JOURNAL
35
http://ashrae.org
ASHRAE Journal - January 2023

Table of Contents for the Digital Edition of ASHRAE Journal - January 2023
