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UofTAgritech / PeaPod

A cloud-connected automated plant growth environment, designed as both a hassle-free food production system and a distributed citizen-science research tool.
MIT License
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[DESIGN] - Gas Exchange #1

Open JLefebvre55 opened 3 years ago

JLefebvre55 commented 3 years ago

@UofTAgritech/mechanical

Completion is tracked in the linked PR.

Design Scope

Design a system to mediate gas exchange between the internal environment and the surroundings.

Purpose

The purpose of the gas exchange system is to control the exhaust of internal air and the intake of fresh air to maintain a desired concentration of CO2/O2/etc. while a) not introducing pathogens and/or other aerosols, and b) not compromising the precision of the internal environment.

Function

Inputs:

Outputs:

It interfaces with/depends on the following systems:

System operation assumes:

Method

Setup:

  1. Connect exhaust port to external exhaust air treatment system (i.e. dehumidification)

Process:

  1. On-demand, both input and output ports activate (shutters open, fans are enabled)
  2. Input port draws in air from surroundings
  3. Output port expels air through filtration and dehumidification system to be recycled

Shutdown:

  1. Disconnect exhaust port from filtration/dehumidification system

Features

Each feature should be added to relevant BoMs and CADs where applicable. Design decisions should be well-supported using relevant research and calculations, and should be documented in the Solution Overview. If a feature is complex enough, create a new issue for it using this template, and tag it here.

Requirements and Validation

What does this design need to accomplish? How do we know it has accomplished this?

List any applicable metrics with criteria/constraints, applicable to purpose, function, method, and each feature, as well as how to test them.

  1. Maximum gas exchange throughput -> complete air replacement for a 4-unit setup in X minutes
  2. Filtration > 99% of pathogens (viral, bacterial, and otherwise) as well as aerosols (pollen, etc.)
  3. Shutter mechanism is air-tight (~0% throughput) when closed

Verification

Each test should be performed and documented, and the testing documentation attached to the PR. The testing suite should address the full scope of the function (i.e. ensure inputs are met and outputs work), method (all steps execute correctly), and features (each feature performs as expected) with respect to the purpose and requirements.

How does this design achieve its method effectively, safely, and reliably? How do we test this?

Specific testing procedure:

  1. Test shutter and fan operation
  2. Test shutter air-tightness
  3. Test air throughput (maximum and control precision)
  4. Test aerosol filtration(?)

Additional context

Add any other context about the design scope or additional deliverables here.

Add any relevant electronics to the Wiring Diagram

JLefebvre55 commented 3 years ago

ToDo: