Zehnder Case Study | ComfoPost, Ventilation and Post-Cooling

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Residential property in Modena, Italy: Overheating reduction with balanced ventilation and post-cooling Case Study

Residential property in Modena, Italy

The house and its ventilation system

Introduction With residential properties becoming increasingly well insulated and airtight, achieving good indoor air quality and maintaining a comfortable environment is one of the challenges of modern living.

In future climate scenarios, there is a greater risk of overheating in modern buildings, particularly in urban areas where natural ventilation is less feasible due to noise, burglary risk and higher particulate air pollution levels.

The house and its ventilation system • • •

The objective To establish the effectiveness of heating and cooling indoors at a range of outdoor temperatures across different seasons; summer, autumn and winter.

The project Zehnder monitored the temperature and humidity levels in a nearly zero energy consumption property, in Modena, northern Italy, for seven months.

Equipped with the Zehnder ComfoAir Q600 with post-cooling functionality, the detached house is situated in Formigine where the summers are warm and mostly clear, and the winters are very cold and partly cloudy, thereby providing the ideal base for testing.

This case study summarises the findings and explains how the ComfoAir MVHR system supports the property to achieve a comfortable indoor climate.

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ComfoAir Q600 ERV, maximum airflow rate 600 m3/h (166l/s)(balanced ventilation with enthalpy recovery) ComfoPost CW10, maximum heating output 5.21 kW and cooling output 4.57 kW Heatpump 4 kW dedicated for heating and cooling the water for the ComfoPost ComfoPost is controlled by room thermostat in the living room The balanced ventilation system with enthalpy exchanger is equipped with the Zehnder ComfoPost. The enthalpy exchanger recovers thermal and latent energy from extracted stale air and transfers it into the incoming fresh air stream.

ComfoPost heats or cools the supply air based on the heat pumps water flow, activated by a room thermostat. In the summer the system cools and dehumidifies fresh air and in the winter the air is heated.

Key Advantages ComfoAir Q600

 Comfort ventilation unit with air volume of up to 600 m3/h at 200 Pa  Optimum 96% heat recovery efficiency  100% full and filtered modulating summer bypass  Passive House certified

ComfoPost CW10  Can support satisfaction of SAP 10 or TM59 requirements  Low pressure losses  For use with modular ComfoWell manifolds  Suitable for Passive House application

Residential property in Modena, Italy

The house and its ventilation system

Introduction With residential properties becoming increasingly well insulated and airtight, achieving good indoor air quality and maintaining a comfortable environment is one of the challenges of modern living.

In future climate scenarios, there is a greater risk of overheating in modern buildings, particularly in urban areas where natural ventilation is less feasible due to noise, burglary risk and higher particulate air pollution levels.

The house and its ventilation system • • •

The objective To establish the effectiveness of heating and cooling indoors at a range of outdoor temperatures across different seasons; summer, autumn and winter.

The project Zehnder monitored the temperature and humidity levels in a nearly zero energy consumption property, in Modena, northern Italy, for seven months.

Equipped with the Zehnder ComfoAir Q600 with post-cooling functionality, the detached house is situated in Formigine where the summers are warm and mostly clear, and the winters are very cold and partly cloudy, thereby providing the ideal base for testing.

This case study summarises the findings and explains how the ComfoAir MVHR system supports the property to achieve a comfortable indoor climate.

•

ComfoAir Q600 ERV, maximum airflow rate 600 m3/h (166l/s)(balanced ventilation with enthalpy recovery) ComfoPost CW10, maximum heating output 5.21 kW and cooling output 4.57 kW Heatpump 4 kW dedicated for heating and cooling the water for the ComfoPost ComfoPost is controlled by room thermostat in the living room The balanced ventilation system with enthalpy exchanger is equipped with the Zehnder ComfoPost. The enthalpy exchanger recovers thermal and latent energy from extracted stale air and transfers it into the incoming fresh air stream.

ComfoPost heats or cools the supply air based on the heat pumps water flow, activated by a room thermostat. In the summer the system cools and dehumidifies fresh air and in the winter the air is heated.

Key Advantages ComfoAir Q600

 Comfort ventilation unit with air volume of up to 600 m3/h at 200 Pa  Optimum 96% heat recovery efficiency  100% full and filtered modulating summer bypass  Passive House certified

ComfoPost CW10  Can support satisfaction of SAP 10 or TM59 requirements  Low pressure losses  For use with modular ComfoWell manifolds  Suitable for Passive House application

Findings

Findings

How Zehnder ensured consistent monitoring

The results show that indoor temperatures remain comfortable at between 19°C and 27°C whilst outdoor temperatures fluctuate seasonally between -5°C and 40°C.

The flow rates in the fan positions low, middle and high were set at 180, 250 and 420 m3/h (50, 69 and 116 l/s). Monitoring took place from 3 August 2017 until 8 March 2018, enabling the capture of both summer (cooling) and winter (heating) output. The house has no other internal climate control devices.

Monitoring results Summer • Outdoor temperatures in the daytime were up to 40°C and around 25°C at night • Indoor temperatures reached a maximum of 27°C with outdoor temperatures up to 40°C • Ventilation air was post-cooled during the daytime to a supply temperature of between 11°C and 20°C, when requested by the room thermostat Autumn • Outdoor temperatures between 10°C and 15°C lead to supply temperatures of fresh air at around 20°C • The indoor temperature of 22°C is fairly constant Winter • Outdoor temperatures were as low as -5°C at night and up to 11°C during the day • Temperatures recorded indoors were around 20°C at night and 25°C in the day Results of the monitoring can be clearly seen in the graph below where post-supply temperature is compared to the temperature outdoors across various ventilation system modes.

In summer, outdoor heat is rejected due to the cold recovery from colder indoor air. In autumn, the indoor temperature is fairly constant due to the recovery of indoor heat. In winter, temperatures recorded indoors were around 20°C at night and 25°C in the day due to the ComfoAir Q’s market leading heat recovery efficiency combined with the post-heating.

Zehnder’s study of the house in Modena measures the effectiveness of a balanced heating and ventilation solution through fluctuating climates.

Conclusion The results show that the overheating problem in this house is reduced by the mechanical ventilation system, even when summer outdoor air temperature and humidity are higher than indoors.

The study confirms that balanced ventilation offers an ideal solution, keeping indoor conditions hygienic, and at a comfortable temperature, effectively and efficiently preventing overheating.

A ventilation solution for the future The modern ventilation debate has moved on from the question of whether a ventilation system is necessary. Serious discussion amongst specialists in the built environment, including architects, developers and policy decision makers, is now very much focused on the vital role ventilation has to play in the prevention of overheating in homes of the future. Ventilation systems can play an integral role, in the challenge to meet Net Zero goals through reducing heat output required, due to the optimum 96% heat recovery efficiency of our ComfoAir Q MVHR unit. The ability to deliver optimum indoor climate and adhere to low carbon output targets are no longer a luxury; these are essential.

The results also endorse the low running cost of this form of heating and cooling via the ventilation unit.

The monitoring demonstrated approximately 3 kW of heating and cooling were sufficient to ensure a comfortable environment in the house and prevent overheating.

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Zehnder • Concept House • Watchmoor Point • Camberley • GU15 3AD T +44 (0) 1276 605800 • info@zehnder.co.uk • www.zehnder.co.uk Zehnder is a division of Zehnder Group UK Ltd • Registered in England 2296696

Findings

Findings

How Zehnder ensured consistent monitoring

The results show that indoor temperatures remain comfortable at between 19°C and 27°C whilst outdoor temperatures fluctuate seasonally between -5°C and 40°C.

The flow rates in the fan positions low, middle and high were set at 180, 250 and 420 m3/h (50, 69 and 116 l/s). Monitoring took place from 3 August 2017 until 8 March 2018, enabling the capture of both summer (cooling) and winter (heating) output. The house has no other internal climate control devices.

Monitoring results Summer • Outdoor temperatures in the daytime were up to 40°C and around 25°C at night • Indoor temperatures reached a maximum of 27°C with outdoor temperatures up to 40°C • Ventilation air was post-cooled during the daytime to a supply temperature of between 11°C and 20°C, when requested by the room thermostat Autumn • Outdoor temperatures between 10°C and 15°C lead to supply temperatures of fresh air at around 20°C • The indoor temperature of 22°C is fairly constant Winter • Outdoor temperatures were as low as -5°C at night and up to 11°C during the day • Temperatures recorded indoors were around 20°C at night and 25°C in the day Results of the monitoring can be clearly seen in the graph below where post-supply temperature is compared to the temperature outdoors across various ventilation system modes.

In summer, outdoor heat is rejected due to the cold recovery from colder indoor air. In autumn, the indoor temperature is fairly constant due to the recovery of indoor heat. In winter, temperatures recorded indoors were around 20°C at night and 25°C in the day due to the ComfoAir Q’s market leading heat recovery efficiency combined with the post-heating.

Zehnder’s study of the house in Modena measures the effectiveness of a balanced heating and ventilation solution through fluctuating climates.

Conclusion The results show that the overheating problem in this house is reduced by the mechanical ventilation system, even when summer outdoor air temperature and humidity are higher than indoors.

The study confirms that balanced ventilation offers an ideal solution, keeping indoor conditions hygienic, and at a comfortable temperature, effectively and efficiently preventing overheating.

A ventilation solution for the future The modern ventilation debate has moved on from the question of whether a ventilation system is necessary. Serious discussion amongst specialists in the built environment, including architects, developers and policy decision makers, is now very much focused on the vital role ventilation has to play in the prevention of overheating in homes of the future. Ventilation systems can play an integral role, in the challenge to meet Net Zero goals through reducing heat output required, due to the optimum 96% heat recovery efficiency of our ComfoAir Q MVHR unit. The ability to deliver optimum indoor climate and adhere to low carbon output targets are no longer a luxury; these are essential.

The results also endorse the low running cost of this form of heating and cooling via the ventilation unit.

The monitoring demonstrated approximately 3 kW of heating and cooling were sufficient to ensure a comfortable environment in the house and prevent overheating.

1

2

5 3

4

6

Zehnder • Concept House • Watchmoor Point • Camberley • GU15 3AD T +44 (0) 1276 605800 • info@zehnder.co.uk • www.zehnder.co.uk Zehnder is a division of Zehnder Group UK Ltd • Registered in England 2296696