Bitcoin mining rigs solves complex math problems, compete for bookkeeping rights and receive block rewards. They usually contain mining chips (ASIC), heat sinks and fans.
Mining rigs consume a lot of energy while crunching algorithms. Mining is essentially a competition of computing power, miners who have more powerful rigs have higher chances of mining Bitcoins.
When the network sees an increased level of computing power, mining becomes more difficult with traditional setups (CPU or GPU), And therefore, specialized mining chips (ASIC) are invented. The mining chip (ASIC) is the core component in the rig. Rigs can get overheated during the process hence heat sinks and fans are installed for cooling purposes.
Miners can download the mining software and allocate tasks to each rig, then they can start mining. The algorithm for each cryptocurrency is different, requiring different types of rigs.