Secop's Solar Direct Drive (SDD) System Earns WHO PQS Approval – The Team Behind It

In March 2026, Secop’s Solar Direct Drive Power Management Module was granted WHO PQS prequalification and officially listed in the WHO Catalogue of Prequalified Immunization Devices.

The WHO IMD-PQS (Immunization Devices Performance, Quality and Safety programme) is the global benchmark for cold chain equipment used in immunisation. Being listed in its catalogue is a verified technical certification that a product meets the W.H.O. requirements for performance, quality and safety: the standard that UN agencies and national immunisation programmes worldwide use to select equipment for procurement. The only path is through the process itself, which includes pre-submission screening, full dossier evaluation, accredited laboratory testing, and independent technical review, with a maximum of three rounds before an application is rejected entirely.

For Secop, this milestone is the result of months of close collaboration between its engineering team and WHO technical officers: a journey that began before the formal application, when Secop joined a WHO industry working group on equipment monitoring systems.

Below are questions posed directly to Secop engineers and project leads who contributed to this achievement, offering insight into their experiences and the effort involved.

Solar Direct Drive and Weak Grid Power Management System

04.2026 | Literature | Leaflets
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Peter Michael Hansen

Medical Business Director

The WHO PQS prequalification positions Secop as an official contributor to global humanitarian immunisation efforts and confirms the reliability of the brand in the medical cold chain. What does this mean for the company’s vision, and what does it mean to you personally that this technology will help protect some of the world’s most vulnerable communities?

The true progress here is that Secop is now officially listed in the WHO PQS catalogue. We have long played a role in the cold chain with our dedicated medical compressor range, and our products have been used in certified applications for years. But now, for the first time, we have a product developed by Secop that is part of the catalogue itself. That is a meaningful step forward for us as a company.

And the significance of that step becomes clear when you look at what is at stake. Vaccination has saved 154 million lives since 1974, and reliable cold chain infrastructure is what makes that possible. Yet the World Health Organization estimates that up to 50% of vaccines are still wasted globally every year, largely because of failures in temperature control and cold chain logistics. Every percentage point of that waste we can reduce means more doses reaching the people who need them. We built this system to make reliable cold chain genuinely accessible in places where electricity cannot be taken for granted. We are the only compressor manufacturer with a dedicated medical portfolio built specifically for this field. Now we are also the only one with a device in the WHO PQS catalogue. That is not a detail. That is who we are.

Sources:

Helmut Greiner

Project Leader & Head of Medical Application Engineering

The SDD system had to perform reliably across an extraordinary range of real-world conditions like usage of photovoltaic panels, unstable grids, or in extreme case even with no power from grid at all. What did it take to engineer a system that works in all these scenarios, and what makes this solution genuinely different from what existed before?

The fundamental challenge was this: the system must work regardless of what is happening outside. On a grid that swings anywhere from 82 to 274 volts AC, and survives surges up to 510 volts, without requiring an additional voltage stabilizer. On solar panels, optimized for the latest generation of 72-cell PV panels, with an MPPT algorithm that continuously adapts compressor speed to whatever sunlight is available, so the system keeps running even when irradiation is at a low level. And it delivers up to 110 watts constantly.

The new SDD2 power management system handles a smart selection of powering by sun preferably and seamless transfer to grid when sun irradiation goes below a minimum level, without manual intervention. That is what changes everything for a clinic in a remote area: universal SDD2 can be used in every area and condition and cooling for medical cold-chain simply does not stop. Beyond this, SDD2 has been developed to fulfill new WHO-PQS-E006 requirements to monitor and transfer all essential physical cooling parameters to enable remote supervision and timely service interventions to avoid down-time and waste of life-saving vaccines.

Hendrik Möller

Head of Application Engineering DC

The Secop SDD system brings together the WHO PQS-approved Power Management Module, the Solar dedicated controller, and the MB3CKV compressor as a fully integrated solution. What problem does this solve for manufacturers, and how does it compare to what the market offered before?

Before this system existed, manufacturers building solar-capable vaccine refrigerators had two choices. They could either combine the previous version of the Secop Solar Direct Drive with Secop components and their own measurement equipment to fulfill the latest PQS logging and data acquisition requirements, or they could source and integrate separate components, often from different suppliers, and validate the entire system against WHO specifications themselves. This was a significant engineering burden and risk.

Secop now offers an evolution of the pre-integrated combination: one solar power management module, one compressor, and one dedicated solar compressor controller. These components are designed and validated to work together, and they are pre-approved by the WHO PQS group. Using the latest technologies, such as the BD Nano compressor, which is adapted for medical purposes; the solar compressor controller, which has special start-up algorithms that improve start-up in low-light conditions; and the PQS-approved power management module, which allows users to read PQS-related information about the vaccine refrigerator’s status, as well as peak power point tracking to ensure optimal use of available sunlight. Having a single integrated, pre-approved system at the core removes a layer of complexity that used to cost manufacturers a lot of engineering resources and development time.

Thomas Krogh Nielsen

Director Global Approbation

From an external perspective, the complexity of obtaining this certification can be challenging to fully understand. Can you describe the challenges associated with this process and the approaches taken to successfully obtaining the certification?

It is not a certification in the traditional sense; rather, it constitutes a sustained and highly rigorous dialogue with some of the most demanding technical evaluators in the world, conducted under strict procedural constraints. Candidates are permitted a maximum of three review rounds. Failure to meet the required standard by the third round results in rejection, necessitating a complete reapplication from the outset. Each review cycle requires responses that are comprehensive, precise, and fully documented, leaving no room for ambiguity or interpretive flexibility. The certification process for the SDD system took approximately seven months (1 October 2025 to 1 April 2026). A critical factor in our successful outcome was our prior involvement in the WHO working group, which preceded the formal application phase. This early engagement enabled us to develop a deep understanding not only of the technical specifications themselves, but also of the underlying rationale informing them. That level of preparation proved to be decisive.

Sistema solar de accionamiento directo, R600a

Sistema solar de accionamiento directo, R600a