Product Overview

The Bitmain Antminer S21 Hydro 358T is a hydro-cooled Bitcoin (BTC) SHA-256 ASIC miner delivering 358 TH/s at approximately 5,002W. Based on the S21 platform with hydro-cooling applied, the S21 Hydro 358T delivers higher hashrate per unit than the air-cooled S21 series by removing the thermal constraints that limit fan-cooled designs — while maintaining compatibility with the established S21 platform architecture.

The S21 Hydro 358T occupies the mid-range of Bitmain’s hydro-cooled Bitcoin mining lineup — offering more hashrate than the air-cooled S21 XP 270Th at broadly comparable efficiency, but less than the more advanced S21 XP Hydro 473T. For commercial operators building out a hydro-cooled mining infrastructure, the S21 Hydro provides a cost-effective entry into the hydro-cooled hashrate tier.

For South African operators, the S21 Hydro 358T’s infrastructure requirements — a hydro-cooling loop and high-amperage electrical supply — place it firmly in the commercial mining category. The near-silent operation compared to air-cooled equivalents is a meaningful benefit for facilities where ASIC fan noise is a concern.

Key Features

• 358 TH/s SHA-256 Hashrate (±3%): High Bitcoin mining output enabled by hydro-cooling on the S21 platform. Significantly more than air-cooled S21 variants.
• Hydro-Cooled S21 Platform: Liquid cooling applied to the proven S21 ASIC architecture — enabling higher sustained hashrate without air-cooled thermal constraints.
• ~14 J/TH Power Efficiency: Competitive efficiency for the S21 hydro-cooled platform at this hashrate tier.
• 5,002W Power Consumption: High power draw requiring dedicated high-amperage electrical infrastructure beyond standard 32A single-phase circuits.
• Near-Silent Operation: Without high-speed fans, the S21 Hydro 358T operates near-silently — a significant noise reduction versus air-cooled equivalents.
• S21 Platform Compatibility: Built on Bitmain’s established S21 ASIC architecture with known firmware ecosystem and mining pool compatibility.
• Standard Ethernet Management: Compatible with major Bitcoin mining pools and ASIC management platforms.

Technical Specifications

• Algorithm: SHA-256
• Supported Coins: Bitcoin (BTC), Bitcoin Cash (BCH), and other SHA-256 cryptocurrencies
• Hashrate: 358 TH/s (±3%)
• Power Consumption: ~5,002W (±5%)
• Power Efficiency: ~14 J/TH
• Cooling Type: Hydro-cooled (liquid cooling loop required)
• Noise Level: Near-silent (no fans)
• Input Voltage: 200–240V AC, 50/60 Hz
• Networking: 1× RJ45 Ethernet
• Power Supply: Confirm inclusion at time of purchase

Power & Installation Notes

The Antminer S21 Hydro 358T draws approximately 5,002W continuously. This exceeds standard 32A single-phase circuit capacity — a 40A or higher dedicated circuit is required, ideally from a three-phase supply for multi-unit deployments. All installation must comply with SANS 10142 and be certified by a registered electrician.

The hydro-cooling loop is the essential additional installation requirement: circulation pumps, coolant piping, heat exchanger manifold, and a dry cooler or cooling tower for external heat rejection. This infrastructure must be correctly engineered for the 5,002W thermal load. Specialist hydro-cooling integrators should design and install this system before the miner is commissioned.

Load shedding at 5,002W cannot be managed with any standard inverter system. Commercial generator capacity is required for operations that need to maintain uptime through South African power outages.

Electricity Cost Context — South Africa

At R2.80/kWh reference tariff, the estimated monthly electricity cost is:

(5002 ÷ 1,000) × 24 × 30 × 2.80 = R10084.03 per month

This is an operating cost estimate only. Commercial and industrial electricity tariffs vary significantly from residential reference figures. The S21 Hydro 358T’s efficiency at 14 J/TH is competitive for a hydro-cooled Bitcoin miner at the 350+ TH/s tier.

Ideal Use Cases

• Commercial Bitcoin mining with hydro-cooling: The S21 Hydro 358T is designed for large-scale commercial operations with purpose-built hydro-cooling infrastructure and industrial electrical supply.
• Entry into hydro-cooled Bitcoin mining: For operations planning to transition from air-cooled to hydro-cooled infrastructure, the S21 Hydro platform provides an entry point below the S21 XP Hydro 473T in terms of both hashrate and power draw.
• High-density data centre deployments: Hydro-cooled miners enable more TH/s per square metre than air-cooled equivalents — relevant for operations where data centre space is the primary constraint.
• Noise-sensitive facilities: Near-silent operation for facilities where ASIC fan noise is an operational or compliance concern.

Frequently Asked Questions

Does the S21 Hydro 358T require special plumbing?
Yes — a complete closed-loop liquid cooling system is required, including circulation pumps, coolant piping, heat exchanger manifold, and external heat rejection. Specialist installation is necessary.

How does the S21 Hydro compare to the S21 XP Hydro 473T?
The S21 XP Hydro 473T delivers 115 TH/s more hashrate at similar power but better efficiency (~12 J/TH vs ~14 J/TH for the S21 Hydro). The S21 XP Hydro is the more efficient and higher-hashrate option; the S21 Hydro 358T is the lower-cost entry into the hydro-cooled Bitcoin mining tier.

Is this suitable for home or small-scale mining?
No. The hydro-cooling requirement and high power draw make this exclusively suited to large-scale commercial mining operations.

Can it handle South African load shedding?
Not without commercial generator capacity. 5,002W exceeds any standard inverter system capability.

Is the PSU included?
Confirm at time of purchase.

What’s Included

• 1× Bitmain Antminer S21 Hydro 358T mining unit
• Cooling manifold/connections (confirm specifications at time of purchase)
• Power supply (confirm inclusion at time of purchase)
• Power cables
• Quick-start documentation