Thermal Storage Coupled to a Ground Source Heat Pump in a Public Services Building COIMBRA Andre Quintino Duarte Oradea, 06 June 2012

Demonstration Building Total area: 3250m 2 Four floors Two public services installed Offices, laboratories, conference room Capacity for 250 permanent workers + 72 temporary people in a conference room Located close to a river “Fábrica dos Mirandas”

Demonstration Building

The heated /cooled spaces are located in level 3 of the building (last floor). 22 rooms (offices) Approximately space conditioned area 600 m 2

22 Rooms

Thermal Solution Before 2012: Air Conditioning –Low Efficiency; –Noisy; –Outdated technology; –COP between 2 and 3. February 2012: Ground Source Heat Pump (GSHP) –High Efficiency; –Very Silent; –New technology; –COP between 5 and 6. November 2012: GSHP + Thermal Storage –Increase Efficiency; –Avoid Expensive Electricity Periods; –Reduce Building Footprint.

Thermal Storage The thermal storage tank is to be located in a room adjacent to the machinery room. It is planned to have a volume of 3.5m 3 (40% water + 60% PCM). Research is being conducted with the support of the Fluids Thermal Transfer Group of the Department of Mechanical Engineering on the best design of the tank to ensure optimal heat transfer and to ensure that the storage maximum capacity of the PCM modules is used. It was found that the most suitable material would be the S46 salt hydrate from PCM products Ltd (UK)

Thermal Storage Tank Tank Dimensions: 1,5m; 0,8m; 3m (H; W; L) With a Thermal Capacity of 100 KWh. (Currently under construction) To be installed late this year in November.

Thermal Needs on a Typical Monday 100 kWh Thermal Storage for 2 hours.

Thermal Needs on a Typical Friday 100 kWh Thermal Storage for 3,5 hours.

Electricity Price in Portugal Period Electricity PricesPeak Power Prices Peak Period 9 AM to 10:30 AM 6 PM to 8:39 PM 0,2078 €/kWh0,4025 €/kW Middle Peak Period 8 AM to 9 AM 10:30 AM to 6 PM 0,1112 €/kWh- Off Peak Period 10 PM to 2 AM 6 AM to 8 AM 0,0732 €/kWh- Special Off Peak Period 2 AM to 6 AM0,0680 €/kWh-

Control System

Control Hardware

Piping System

Heat Pump Reversibility is done on the water side in order to always be in counter current on the heat exchangers. This is achieved by 3-way motorized valves

Simplified Schematics of the Hydraulic Installation 75 mm Diameter PPR Pipes in the main sections Thermal Storage

Control Software

Preliminary Test Results Without Thermal Storage: COP = 6,03 With Thermal Storage: (In November)

Thank you