Indianised Mini Server Rack

Rationale

India has a unique set of challenges when it comes to server racks, including high temperatures, dust, and power fluctuations. These conditions are not occasional occurance, but rather a constant challenge that needs to be addressed in a way that works long term. Power outages can be frequent and prolonged, authorities are not answerable, which means we need extended back up solutions which can possibly be solar powered perpertually. Air quality issues also don’t seem to have any solutions as problems are political rather than techincal. Which means we must design the server to work under these conditions till the end of life.

My Indianised Mini Server Rack is designed to address these issues while providing a compact and efficient solution for my home lab. It has a centralized air handling unit which provides filtered air through a duct to all racks, with servo controlled dampers to regulate airflow. The system maintains a positive pressure environment to prevent dust ingress, and so the design can be very open for allowing natural convection when heat load is low. It also has an online UPS system with 1Kwh of LiFePO4 battery storage to provdide estimated 15 hours of backup power for the entire rack in case of power outages. The battery charging circuit is fully programmable, supports MPPT and is controlled by power controller MCU. The charging circuit’s input can be selected between SMPS and solar panels. The UPS part is connected to network and runs Network UPS Tools (NUT) to provide power status to all servers and network devices. The system is designed to be modular and scalable, allowing for easy expansion as my needs grow.

System Overview

Major subsystems of my Indianised Mini Server Rack include:

• Power distribution
• Cooling and ventilation
• Backup power supply
• Server management
• Network infrastructure

Power Distribution

Power distribution system consists of central command and control unit which connects to network as well as input and output switches. All systems in this rack are powered through this unit. We will cover each section in details:

• Central Power Command and Control Unit
• Input Power Routing Switch
• Output Power Routing Switch
• Main Power Supply Unit
• Charging Power Supply Unit
• Solar Power Input

Central Power Command and Control Unit

The central power command and control unit is the brain of the power distribution system. It monitors and controls the power flow to all subsystems in the rack. It is responsible for managing the input power routing, output power switching, and programming the programmable battery charging circuit. It also provides network connectivity for remote monitoring and control of the power distribution system. This system consists of an ESP32-S3 microcontroller and a Raspberry Pi Zero 2W computer. The ESP32-S3 handles the real-time control of the power distribution system, while the Raspberry Pi Zero 2W provides a user interface and network connectivity. The ESP32 and Raspberry Pi communicate over a serial connection, allowing for seamless integration of the two systems which does not depend on network switches. The Raspberry Pi runs Network UPS Tools (NUT) to provide power status to all servers and network devices. It also hosts a web interface for remote monitoring and control of the power distribution system.

Input Power Routing Switch

The input power routing switch is responsible for routing the input power from either main power supply unit or solar input to the battery charging circuit. It is controlled by the central power command and control unit, which determines the optimal power source based on the current conditions and user input. The hardware consists of a 2 channel 30A relay module, which is controlled by the ESP32-S3 microcontroller. The relays are used to switch between the main power supply unit and the solar input, ensuring that the battery charging circuit receives power from the appropriate source.

Output Power Routing Switch

This module is responsible for sending power to each device in the server rack.