SACR · -60℃ · 1–50 kW
Engineering notes and reference library for cryogenic refrigeration
Cycle principles, component selection limits, commissioning and troubleshooting for -60℃ single-stage auto-cascade (SACR) units. Written for engineers who need the equipment to actually hold.
Six Design Principles
Stability · Quiet · Precision · Speed · Reliability · Control — the six constraints that shape the product, and the structure of this library.
STemperature Stability
Control accuracy and long-term drift suppression
QLow Noise & Vibration
Vibration isolation and noise source control
PPrecision Manufacturing
Machining accuracy, assembly tolerance, leak testing
VPull-Down Rate
Heat load matching and capacity margin
ROperational Reliability
Oil return, defrost, continuous operation
CIntelligent Control
Data logging, remote monitoring, alarming
Technical Notes
Cycle principles, component selection boundaries, refrigerants and materials, control strategy, installation, commissioning and troubleshooting. Organised by engineering problem.
02 / CASESCase Studies
Unit configuration and actual operating results under different conditions, archived.
03 / DOWNLOADSDownloads
Catalogues, selection tables, interface drawings and commissioning checklists.
Featured Articles
-60℃ single-stage auto-cascade refrigeration · engineering archive
Single-Stage Auto-Cascade (SACR) Cycle Overview: The Full Chain from Refrigerant Pairing to Dephlegmator Separation
Breaks down the refrigerant pairing logic, the dephlegmator separation chain and the role of each component in a -60℃ single-stage auto-cascade cycle, and compares the structural differences against two-stage compression and cascade systems, so that a coherent set of criteria is in place before selection and commissioning.
Compressor Pressure Ratio Boundaries at -60℃: Dividing Criteria Between Scroll and Semi-Hermetic Reciprocating
Starting from pressure ratio, discharge temperature, motor cooling and part-load behaviour, this page gives the dividing criteria between scroll and semi-hermetic reciprocating compressors for -60℃ auto-cascade units, together with an acceptance criterion for each step, for item-by-item checking during selection.
不降温、降温慢、低压报警：-60℃ 自复叠机组故障树与排查顺序
以三类故障现象为起点建立故障树，覆盖压缩机、油路、分凝效率、配比漂移、冰堵脏堵、膨胀元件与电控信号，给出先易后难的排查顺序与每步判据。
自复叠混合工质配对：沸点差、组分比与分凝可行性的判据
说明自复叠为何必须使用非共沸混合工质，沸点差与相对挥发度如何决定分凝可行性，组分比如何定，以及配比漂移的成因与判据。
Frequently Asked Questions
What is the essential difference between SACR, two-stage compression and cascade systems?
The difference is how low temperature is achieved. Single-stage auto-cascade uses one compressor and relies on a zeotropic mixture separating in a dephlegmator, concentrating the low-boiling component for the low-temperature side. Two-stage compression splits the pressure ratio across two stages. A cascade system uses one high-stage cycle to provide cooling for a separate low-stage cycle. Structural complexity and pressure-ratio allocation differ across the three.
Where is the dividing line between scroll and semi-hermetic reciprocating compressors?
The split is by capacity range and operating pressure ratio — not by brand or price. Scroll types are typical at lower capacities; semi-hermetic reciprocating at higher capacities and high pressure ratios. A rising pressure ratio brings discharge temperature and motor cooling issues, which require liquid or vapour injection to be evaluated.
Why are performance figures shown as placeholders?
This site does not publish performance data that has not been measured. Values relating to the unit itself — capacity, power input, COP, pull-down rate, noise — are marked with placeholders until measured data replaces them. Publicly available refrigerant property data may be used, with source and reference basis stated.
Is this a product marketing site?
No. It is a technical archive: cycle principles, selection limits, commissioning and troubleshooting. No product promotion, no competitor comparison.