JP | JPY
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- Challenges and Chances: A Review of the 1st Stem Cell Community Day
- Summertime, and the Livin’ Is Easy…
- Follow-on-Biologics – More than Simple Generics
- Bacteria Versus Body Cells: A 1:1 Tie
- Behind the Crime Scene: How Biological Traces Can Help to Convict Offenders
- Every 3 Seconds Someone in the World Is Affected by Alzheimer's
- HIV – It’s Still Not Under Control…
- How Many Will Be Convicted This Time?
- Malaria – the Battle is Not Lost
- Physicians on Standby: The Annual Flu Season Can Be Serious
- At the Forefront in Fighting Cancer
- Molecular Motors: Think Small and yet Smaller Again…
- Liquid Biopsy: Novel Methods May Ease Cancer Detection and Therapy
- They Are Invisible, Sneaky and Disgusting – But Today It’s Their Special Day!
- How Many Cells Are in Your Body? Probably More Than You Think!
- What You Need to Know about Antibiotic Resistance – Findings, Facts and Good Intentions
- Why Do Old Men Have Big Ears?
- The Condemned Live Longer: A Potential Paradigm Shift in Genetics
- From Research to Commerce
- Chronobiology – How the Cold Seasons Influence Our Biorhythms
- Taskforce Microbots: Targeted Treatment from Inside the Body
- Eyes on Cancer Therapy
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- Challenges and Chances: A Review of the 1st Stem Cell Community Day
- Summertime, and the Livin’ Is Easy…
- Follow-on-Biologics – More than Simple Generics
- Bacteria Versus Body Cells: A 1:1 Tie
- Behind the Crime Scene: How Biological Traces Can Help to Convict Offenders
- Every 3 Seconds Someone in the World Is Affected by Alzheimer's
- HIV – It’s Still Not Under Control…
- How Many Will Be Convicted This Time?
- Malaria – the Battle is Not Lost
- Physicians on Standby: The Annual Flu Season Can Be Serious
- At the Forefront in Fighting Cancer
- Molecular Motors: Think Small and yet Smaller Again…
- Liquid Biopsy: Novel Methods May Ease Cancer Detection and Therapy
- They Are Invisible, Sneaky and Disgusting – But Today It’s Their Special Day!
- How Many Cells Are in Your Body? Probably More Than You Think!
- What You Need to Know about Antibiotic Resistance – Findings, Facts and Good Intentions
- Why Do Old Men Have Big Ears?
- The Condemned Live Longer: A Potential Paradigm Shift in Genetics
- From Research to Commerce
- Chronobiology – How the Cold Seasons Influence Our Biorhythms
- Taskforce Microbots: Targeted Treatment from Inside the Body
- Eyes on Cancer Therapy
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JP | JPY
The Core of Cooling - The Compressors
Lab Academy
Within a ULT freezer, there are parts which support cooling passively (e.g. insulation or gaskets) as well as active cooling parts as the compressors. The compressors are literally the core of every freezer.
How can you create coldness?
The compressor creates coldness indirectly: Within the compressor, the cooling gas is compressed. The gas leaves the compressor while being pressurized and heated-up gas. After the compressor, the compressed gas reaches the condenser where the gas liquefies. The temperature of the liquid is still high. By passing a so-called expansion valve, the pressure of the liquid is drastically reduced within a very short timeframe. By this flash-like evaporation from liquid to gas phase, coldness is created. This coldness within the cooling pipe is transferred to the cooling loops which enclose the freezer chamber. Locally, the coldness is passed to the stainless-steel interior walls of the inner freezer chamber. The cooling loops are even visible at the beginning of the cooling process when you cool down the freezer.Why are there 2 compressors?
The major suppliers of ULT freezers trust in 2-stage compressor systems. Within this 2-stage or 2-loop systems, there are two temperature levels. Simplified, the temperature of the first coolant is cooled down from room temperature to -45 °C by the first compressor. The heat exchanger transfers the coldness of -45°C from the first stage to the second stage. Afterwards, by using the compressor of the second stage, the coolant of the second stage is cooled down from -45 °C to -86 °C. This split into two steps enables a smooth and reliable running of the single compressor per step as they work in a kind of comfort zone. The used coolants work in a very efficient way as their pressure and temperature range are optimized for the first stage respective the second stage. When using just one compressor or even a Stirling engine to cool down from +20 °C room temperature to -86 °C, more than 100 °C must be spanned in one single step. Technically, this works but the load for the cooling system is much higher.The 2-stage system is very durable approach, supported in well-known ULTs by high-value compressors from benchmark suppliers.
How can you extend the lifetime of your compressors?
Standard high-quality compressors have a long lifetime but there are still some aspects which might extend their lifetime:
- Keep distance of at least 150 mm towards walls, other freezer, or furniture for optimal heat removal
- If you install several freezers in one room, take care of room ventilation, e.g. air condition, especially in summer times
- When you access the freezer, keep the door open times as short as possible
- For efficient heat removal from the condenser, the air filter should regularly be cleaned
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