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Schatzari Cookstove

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Schatzari-1.jpg

Objective[edit]

A Patsari cookstove, nicknamed the Schatzari was built at the Schatz Energy Research Center (SERC) laboratory on May 27, 2010. The purpose of this Appropredia page is to describe the construction process of the Patsari, with a particular focus on the modifications and deviations that were made from the document, “Estufa Patsari; Manual de Construccion (EPMC).” This page is intended to serve as an amendment to the construction manual that was published by the Grupo Interdisciplinario de Tecnologîa Rural Apropiada (GIRA), and should not be considered a stand-alone document. The construction process marks the beginning of a collaboration between GIRA and SERC. The goal is to use the stove as a tool to develop research projects aimed at investigating the relationship between stove combustion design parameters and emissions of black carbon (BC). BC is a major contributor to global warming and accelerated glacial melt. Furthermore, emission of BC inside the home is a public health concern because of its role in causing chronic and acute respiratory diseases in groups that experience significant exposure, particularly in the Global South. This will add to the scientific knowledge base of biomass cookstoves, as they relate to local and global scale emissions inventories of BC and co-pollutants. Past studies have shown that the Patsari’s combustion chamber design increases combustion efficiency, reduces emissions of BC and other particulate matter, and decreases consumption of fuel wood.

Summary[edit]

GIRA members leading the construction process were Omar Masera, Victor Berrueta, and Ilse Ruiz Mercado. SERC members assisting in the construction process were Greg Chapman, Tirian Mink, and Ruben Garcia. The stove was completed and briefly tested on May 28, 2010. The latest version (as of 5/27/10) of the EPMC was followed closely. Any deviations from the manual were made to accommodate the difference between materials procured in Arcata versus Mexico, as well as to accommodate future stove testing. The primary modifications were the addition of air supply lines into the combustion chamber, as well as ducts for the insertion of thermocouples into various locations inside the stove.

Pre-construction Preparation Work[edit]

As specified in the EPMC, a heavy-duty metal table (130cm x 99cm x 78.5cm) capable of supporting several hundreds pounds was procured to serve as a stove base. The table was sanded and cleaned to eliminate rust.

A mold was built from plywood to ensure proper exterior stove dimensions. The mold dimensions (107cm x 70cm x 29cm) were slightly larger than specified in the EPMC, as advised by the GIRA team.


Since local bricks were slightly smaller than that normally used, a brick configuration was designed to fit the mold with the smaller bricks. This required cutting bricks and dry fitting them in the mold through a trial and error process until proper stove dimension were achieved. Since local sand was courser than that normally used, a sieve was built to filter out small rocks (approximately > 1/8" wide).

Bricks were arranged inside the mold and photographed to preserve the exact brick configuration during the brick laying process. It should be noted that the exterior dimensions of the stove are not important so long as the stove can accommodate the combustion chamber interior dimensions of 36cm x 22cm x 12cm, and the cooking surfaces.

Materials[edit]

Sand and gravel
Clay and mortar mix
Description Dimensions Quantity
standard red bricks 20.5cm x 9.5cm x 6.2cm 55-60
yellow fire bricks 23.4cm x 11.9cm x 3.2cm 8-10
Sakrete Types S Masonry Mortar 60-pound bag 2
gravel 25-gallon bucket 4
fine sand 5-gallon bucket 2
H.C. Mortar Clay (A Superior Clay Product) 50-pound bag 1
½“ Hardibacker fireboard 3’x 5’ sheet 1
metal chimney tubes 4” diam x 90 cm 3

Accessories[edit]

Accessories

The following tools and materials were manufactured in Mexico and brought by the GIRA team:

Description Dimensions Quantity
metal chimney base (with two rectangular inlets for secondary burners and one circular outlet for chimney) 9 cm diam., 5cm x 8cm 1
metal secondary burner mold See picture 1
Novaceramic Vintex brick/ with interior holes 105cm x 70cm x 27cm / 8cm x 8cm x 6cm 1
primary burner, 14 gauge steel 54 cm diam 1
secondary burners, 14 gauge steel 28 cm diam 2

Overview of construction process[edit]

Day 1: On Wednesday May 26, 2010, members of GIRA arrived at SERC to take part in a planning session for the following day’s stove construction process. GIRA members observed that due to regional differences in clay, sand, and mortar, sample clay mixtures should be made to determine the optimal mixture. To determine this, different ratios of clay, sand, and mortar were made. The following day, the samples were observed and it was determined the most suitable ratio was 1 part clay, 2 parts sand, and 2 parts mortar (1:2:2).

Day 2: On Thursday May 27, 2010, members of GIRA and SERC built the Patsari cook stove.

Day 3: On Friday May 28, 2010, the chimney was installed and the stove was demonstrated by preparing a batch of quesadillas.

Step-by-step construction process[edit]


Bricks were laid in the following sequence with careful attention focused on maintaining combustion chamber dimensions of 36cm x 22cm x 12cm,

  • Outer-bottom course, including bottom course of combustion chamber (Note: three fire bricks were used as the bottom layer of the combustion chamber and the first course of combustion chamber bricks started from the Hardibacker (not on the fire brick))
  • Outer-middle course, including middle course of combustion chamber (Note: a non-mortared brick should be placed under the combustion chamber opening, to serve as a support for the middle course, until dry.)
  • Outer-top course, not including top course of combustion chamber bricks; the third course of combustion chamber bricks were added after the addition of gravel below.