Amazed by the energy-efficient office retrofit

Project Overview

Project Add:Top-floor commercial office space in Southern city of Zhejiang,China.

Area: 103m2(including 3 independent offices)

Local Climate:

- Summer: High temperature and high humidity (Max. Temp 38°C,RH 70%-80%)

- Winter: Low temperature and high humidity (Min. Temp -5°C, average RH 70%)

Yueqing City falls under the summer hot and winter climate according to China’s climatic heating and cooling classification.

2023 Annual Data:

• · Cooling dehumidification: 988 hours
• · Isothermal dehumidification: 4581 hours
• · Heating dehumidification: 886 hours
• · Heating humidification: 16 hours
• · Isothermal humidification: 117 hours

Annual Humidity Control Strategy: Isothermal dehumidification throughout the year; dehumidification in summer and moisture retention in winter using heat and moisture recovery from ERV fresh air systems, eliminating the need for dedicated humidifiers.

Before the Renovation:

This office‘s air-conditioning system before the renovation, including VRV air-conditioning outdoor units, fan coil indoor units, which led to the cooling must dehumidification, indoor temperature and humidity can not be controlled independently. That users are not satisfied with traditional convection air conditioning system below drawbacks:

• The system must remove moisture from the air to prodvide cooling, which can be lead to an excessively dry indoor enviroment.
• Traditional air conditioners do not allow separate adjustment of temperture and humiditu, making it difficult to manage indoor climate precisely.
• The system often fail to provide consistent cooling across the entire space, resulting in varying temperatures in different areas.
• The cooling process usually involves noticeable air movement, which can be uncomfortavle or drafty for occupants.
  

System Configuration

1. Photovoltaic Power Generation System

- Solar Panels: 20 panels, approximately 63.5 m2

- Power Generation: Power generation 13.2kW, local average annual sunlight duration 1800 hours, daily average 4.9 hours, estimated daily power generation 64.68kWh (according todesign estimate)

- Energy Storage System: 25.56kWh for storing excess energy

2. Air Source Heat Pump

- Model: MG 100DT

- Cooling Rated Power: 10kW

- Heating Rated Power: 9kW

3. Smart Control System

- Ai Digital HVAC: Automatically achieves constant temperature, humidity, oxygen, cleanliness, and quietness based on outdoor climate changes and indoor personalized needs. Features include anti-condensation, climate compensation, and emergency safety strategies for low low-carbonandenergy-saving adaptive operation

- Mobile APP Control: Real-time adjustment of indoor environment

- Remote Cloud Service System: Supports remote maintenance and fault diagnosis

4. Terminal Equipment

- Water-cooled Silent Air Conditioning Panels: No indoorunits or mechanicalequipment, no noise, noairflow sensation; no condensate water,thus preventing mold growth.

- Cooling and Heat Exchange Capacity: 77w/m², maximum capacity 7,954w, coverage rate 78% (77w/m² calculated base on 100m² )

5. Energy recovery Fresh Air System

- G7 Mechanical ventilator with energy recovery

- Energy Recovery Efficiency: 73%

- Airflow: Maximum 450m³/h

- Filter: H13 grade PM2.5 filter with 98% efficiency

System Integration Advantages

1. Green and Energy-Efficient

Photovoltaic Power Generation and Energy Storage System: This project incorporates photovoltaic panels installed on the roof combined with a 25.56 kWh energy storage system, achieving zero carbon emissions through self-generated and self-consumed energy. The photovoltaic system provides approximately 64.68 kWh of energy daily, meeting the daily electricity needs of the entire system. Particularly in summer and autumn, extended sunlight effectively charges the storage system, ensuring stable operation of office equipment. No extra electricity required from on-grid.

The daily electricity consumption of the office is about 40-45 kWh, and 64 kWh of photovoltaic power is generated per day, realising the free of green energy electricity consumption.

2. Efficient and Comfortable Environmental Regulation

Air Source Heat Pump: The project uses the MG 100DT model air source heat pump, which offers efficient cooling and heating capabilities, maintaining a comfortable indoor environment even under extreme weather conditions. With a cooling capacity of 10 kW and a heating capacity of 9 kW, it effectively addresses high temperatures and low temperatures in the local climate.

Water-Cooled Silent Air Conditioning Panels: The end system employs water-cooled silent air conditioning panels made from calcium silicate board, multi-layered oxygen-resistant PE-Xa pipes, uniform aluminum plates, and XPS insulation boards. Utilizing water as the heat medium, the system distributes heat and cold uniformly through large-area radiation, effectively eliminating localized temperature differences typical of traditional air conditioning systems and removing noise and airflow sensations. The maximum radiation capacity of the cooling panels in this project is 99 W/m², with a coverage rate of 78%, providing even cooling across the entire office space.

3. Smart Control and Energy Efficiency

Smart AI Control: The system features AI-based digital HVAC control, which automatically adjusts water temperatures based on indoor dew point temperatures, preventing surface condensation, enhancing comfort, and avoiding energy waste.

Remote Control and Cloud Services: Through a mobile app and remote cloud service system, users can monitor and adjust the indoor environment anytime and anywhere. The system also supports remote fault diagnosis and maintenance, ensuring efficient operation and quick response.

4. Efficient Energy Recovery Ventilator System

G7 Mechanical ventilator with energy recovery: This unit achieves up to 73% heat recovery efficiency, ensuring the introduction of fresh air while minimizing energy loss. The high-efficiency H13-grade filter provides effective PM2.5 filtration, creating a clean air environment in the office space, which contributes to improved employee health and comfort.

Summary

This project successfully integrates advanced photovoltaic power generation, energy storage systems, air source heat pumps, smart control systems, and efficient fresh air systems to create a green, energy-efficient, and comfortable office environment. The combination of photovoltaic and storage systems not only reduces energy costs but also achieves zero carbon emissions, showcasing the potential for sustainable development. The application of air source heat pumps and water-cooled silent air conditioning panels enhances indoor comfort, while the smart control system ensures efficient operation and convenient management. Overall, this integrated system demonstrates outstanding performance in energy conservation, environmental protection, and comfort, reflecting the excellence of modern smart buildings.