Good Practices

Defining the right air change rate for clean rooms

Despite a very clear explanation in the current GMP, FDA, WHO and ISPE guidelines about risk based approach to define the right air changes for cleanrooms, most of the existing cleanrooms have been running at very high air changes which result in very high energy costs with no additional quality benefit. Molen Technic have developed a unique scientific and risk based cleanroom assessment methodology based on historical environmental monitoring data. This methodology have been used to reduce air changes of thousands of cleanrooms at over 100 pharma sites across the world. We helped achieve significant energy and carbon reduction for our global pharmaceutical clients during their Net Zero journeys.

Clean room pressure differentials

It’s not questionable that right pressure differential is crucial to avoid particle ingress from uncontrolled areas and to avoid cross contamination. However it should be considered that the more pressure differential between the adjacent rooms, the more outside air is required. As outside air is hot and humid in summers and cold and dry in winters, pressurization has significant impact on energy consumption of a cleanroom. Molen Technic have assessed thousands of cleanrooms, engineered, recommissioned and qualified them to reduce cost and carbon whilst improved quality.

Contaminant Removal Effectiveness in Clean Rooms

Air change rate is not the only reliable measure for the removal of contaminants. Various factors contribute to the contamination load in a cleanroom, including both human and machine sources. The efficiency of removing this contamination depends on the design of the cleanroom and the initial cleanliness target set for that specific cleanroom. The performance of a cleanroom in removing airborne particles relies on the effectiveness of the ventilation system, which is influenced by the airflow type between the supply air terminals and exhausts, as well as any disturbance of the airflow patterns caused by factors such as obstructions or thermal effects. The air change rate, when used as a “guidance value,” may not encompass all of these variables. By using proper design, it is possible to maintain the same or even improved air distribution and effectiveness in removing contaminants, while using significantly fewer air changes.

Molen Technic utilises risk-based engineering solutions to reduce energy consumption in cleanroom HVAC systems, following the guidelines of ISO 14644-16 “Energy Efficiency in Cleanrooms”. Optimal air change rates will yield the highest removal efficiency and minimise the time required for cleanup, all while avoiding excessive energy use and the associated increase in our carbon footprint.

Dehumidification and Humidification Strategies

Dehumidification and humidification are frequently at the top of the energy usage list in pharmaceutical sites. It is also typically the least energy efficient process and offers enormous energy, cost, and carbon reduction opportunities. This is one of the highest priority areas for Molen Technic evaluations. We question humidity limits with Quality, Production, and Engineering teams to encourage our clients to think outside the box for their own benefit and assist them in determining the appropriate humidity limits for product quality and operator comfort.

Demand Based Cleanroom HVAC System

Cleanroom HVAC systems, like all other HVAC systems used in commercial and industrial applications, can function on demand. Temperature, humidity, pressure differential, and particle counts are typical cleanroom requirements. Cleanroom HVAC systems will gradually transition from classic fixed high air change rated cleanroom control systems to demand-based variable air change rate control systems in the near future.

Demand Based Packaging and Warehouse HVAC System

Because the product is typically enclosed in a secondary packaging process, the area is controlled non-classified (CNC). As such, air conditioning is only required for human comfort and also some companies prefer slightly positive pressure for quality. Secondary packing spaces are one of the largest manufacturing areas on a typical pharmaceutical plant, therefore a fixed speed HVAC system with no demand-based control consumes much more energy than necessary. Warehouses are typically large spaces with ceilings of up to 15 metres. This type of place is likely to be validated, and temperature limitations must be maintained at all levels. Molen Technic offers energy-efficient demand-based HVAC control systems for secondary packaging and warehouses, reducing energy and carbon emissions while enhancing quality and comfort.

Demand Based Laboratory HVAC System

Demand-based control ventilation (DCV) is an intelligent approach used in laboratory ventilation systems. Instead of maintaining a fixed ventilation rate based on initial system design, DCV dynamically adjusts airflow to meet real-time needs. DCV employs real-time data from sensors (occupancy, temperature, contaminants) to determine ventilation rates. When the laboratory is occupied, fume cupboard sashes are open, pollutants are detected, there is more heat gain, the system increases the ventialtion until all the requirements are met. DCV ensures safety, energy efficiency, and can identify issues like malfunctioning fume hoods. Molen Technic design and build state-o-the-art laboratory HVAC systems which reliably maintains comfort and safety at all times whilst operate energy efficiently.

Heat Recovery from Exhaust Air

These systems transfer heat from ventilation exhaust air to warm or cool the incoming fresh air. Heat Recovery systems improves indoor air quality, reduces condensation, and enhances energy efficiency by reusing heat from exhaust air. Some pharma HVAC systems like quality laboratories or hazardous material handling manufaturing processes require 100% outside air supply and exhaust systems which may consume significant heating and cooling energy unless a heat recovery system is considered. Molen Technic surveys, consuct site tests, design and install heat recovery systems on your existing HVAC systems.

Enthaply Control & Free Cooling

An enthalpy control is a strategy to regulate the amount of fresh outside air brought into a space. Its purpose is to meet the cooling or heating demand whilst minimizing energy consumption. It maintains the right balance of temperature and humidity, along with adequate ventilation to remove pollutants and introduce fresh air.

Free cooling is a type of enthalpy control in which temperature is a concern but moisture is not a major requirement. Instead of relying entirely on the cooling mechanism, the free cooling technique rejects heat using the external ambient temperature. It can result in significant energy savings and typically pays for itself within 1-2 years.

Energy Efficient Fans

In many buildings, AHU fans are the largest energy consumers within the HVAC system. Inefficient fans not only waste energy but also impact overall system performance

Our energy-efficient fan experts surveyed, designed, and retrofitted dozens of fans in industrial and commercial buildings. We are independent fan experts who do not represent any brand. As a result, we design and install the most appropriate fan for the purpose. Technical surveys and site tests are essential for proper design and installation.

A new energy efficient fan can save up to 50% of energy with an average payback of 2-5 years.

BMS Optimisation

A poorly operating BMS not only impacts building performance but also affects energy efficiency, occupant satisfaction, and overall cost-effectiveness. We have surveyed and improved BMS of over 100 industrial and commercial facility. Some of the following faults are quite common on Building Management Systems. Faulty sensors, damper and valve actuators temporary open heating and cooling valves that has become permanent Heating and cooling valve hunting due to poorly functioning PID loops Passing heating and cooling valves Single temperature setpoints with no or very narrow headband Unnecessarily low or high temperature and humiditiy setpoints Over humidification or dehumidification due to wrong humidity setpoints.

Our specialist BMS optimisation team survey BMS and address all the issues and improves not only building management system performance but also improves energy efficiency and occupant comfort; and reduces cost and carbon emissions.

Heating and Cooling Generation

Pharmaceutical facilities require steam for process and HVAC systems. Gas steam boilers have long been used to meet these demands. Because of net zero targets, the game is changing. Pharmaceutical businesses are looking for new methods to generate steam without burning fossil fuels while maintaining operational costs low enough to be competitive in the market. There are various options for steam generation, including biomass, hydrogen, and electric boilers, while heat pumps are ideal for HVAC heating.

Heat recovery from chillers and cooling towers can address part of the heating demand by utilising heat pumps.

The solution is not straightforward; it is dependent on demand, local constraints, and opportunities. Molen Technic delivers bespoke engineering solutions for individual site needs based on geographical location.

Heating and Cooling Distribution and Control

Efficient distribution of heating and cooling involves optimizing the delivery of thermal energy throughout the building. Right pipe sizing and distribution strategy, insulation, pump and controls design, control valve type play crucial role on the system efficiency.

Poor steam distribution design or operation can result in significant energy loss.

We have surveyed, designed and improved heating and cooling distribution systems of dozens of pharmaceutical sites across the world.

Clean Steam Generation Methods

Plant steam can be used to produce clean steam from purified water. Electric clean steam is also a popular choice for low-demand applications. However, due to pharmaceutical companies’ net zero ambitions, large-scale electric clean steam generators may become attractive for rapid net zero carbon transition. Molen Technic surveys and evaluates existing systems, present and future demand, and determines the optimum solution that meets the client’s needs.

Water For Injection (WFI) Types

1. Multiple Effect Distillation (MED):

2. Vapor Compression Distillation (VCD):

3. Reverse Osmosis (RO) with Ultrafiltration (UF):

The choice of method depends on factors like scale, energy efficiency, and regulatory compliance. Molen Technic collaborates with site QA, Engineering, and Production teams to determine the best solution for their benefit.