Energy Efficiency Technologies Tecnologie per l'efficienza Energetica

Transcription

1 Energy Efficiency Technologies Tecnologie per l'efficienza Energetica Norma Anglani Department of Electrical Engineering, University of Pavia, via Ferrata 1, Pavia, Italy Piano formativo locale del personale dell'istituto Nazionale di Fisica Nucleare Il problema energetico stato e prospettive, Pavia Novembre 2011

2 In a typical European country the total energy consumption could be broken down as follows: 38% 2% 31% Industry Transport Residential - Tertiary and Agricolture Non energy use 29% Residential and tertiary (along with agricolture) sectors consume the same amount of energy as industry, typically for lighting, HVAC and household appliances, mainly white goods. 2/26

3 ENERGY AND CLIMATE CHANGE In the last twenty years, under the pressure of increasing energy prices, climate change and international agreements such as the Kyoto protocol, Europe achieved significant energy savings in industry, mainly resulting from single investments in process lines, equipment or facilities plants. For this reason it is now harder and more expensive to achieve energy saving. Funding has been made available throughout public Authorities (such as AEEG), amongst several, we mention: white tags for energy saving (roughly /TOE) green tags for electricity production from renewable (roughly 10 c /kwh) 3/26

4 BUILDING CERTIFICATION The energy performance of buildings is a requirement introduced by the European Commission (EPBD EC/91/2002). In Italian legislation since Buildings are classified according to HVAC and lighting consumption and use of renewable energy. Buildings are given a label from A/A+ to G rating (A or A+ being the most efficient, G the less efficient) like for household appliances. (from passive through less than 30 up to 160+ kwh/m 2 ) An energy certificate is needed for any purchase or rental and it may involve depreciation or increase of building value. 4/26

5 WATER MANAGEMENT A complete energy management approach must also consider water consumption in both industrial and tertiary sectors. Saving can be achieved by recovering waste and rain waters, by reducing water discharge from refrigerating systems, by recovering condensate from water vapor pipelines. 5/26

6 BIDIRECTIONAL ENERGY FLOW AND ENERGY SAVING AREAS TN:P (MVC or ABSORPT.) TRASMISSION NETWORK: PIPELINES Petrecca G. Energy Management: principles and applications. Kluwer Ed /26

7 A REVIEW OF ENERGY SAVING TECHNOLOGIES Anglani N., Consoli A. Petrecca G.. Energy Efficiency Technologies for Industry and Tertiary Sectors: the European Experience and Perspective for the Future. IEEE Energy2030 Atlanta, GA USA November The share (ranging from 1 to 5) of current penetration and potential future penetration (~ ) of each technology for industry and for commercial and residential buildings is shown in the following diagram. Average payback time value is also estimated (up to 5 years and more). These values do not consider economic support from Public Authorities. Most of these examples, in particular those related to facility plants, can be applied to all sectors. 7/26

8 COGENERATION, MICRO-COGENERATION AND TRIGENERATION Example with a TG prime mover 8/26

9 Separated commodities supply η=40% 100 η=85% 150 I o η= = = I i CHP as Integrated Service 333 ηe=30% ηt=45% I o η= = =0.75 Ii /26

10 10/26

11 From Anglani N., Petrecca G. A comparison between distributed generation and utility plants: technical, economic and environmental aspects. IEEE EnergyCon, Dec 2010, Manama Bahrain 11/26

12 From Anglani N., Petrecca G. A comparison between distributed generation and utility plants: technical, economic and environmental aspects. IEEE EnergyCon, Dec 2010, Manama Bahrain 12/26

13 COGENERATION, MICRO-COGENERATION AND TRIGENERATION Payback Years Payback Residential buildings Commercial buildings Current Penetration Future penetration Payback Time Industry Penetration (range 1-5) An overall efficiency ranging from 60% to 85% is achievable. Cogeneration is a way of reducing both energy cost for the user and primary energy consumption and GHG emission for the country, if the overall efficiency is higher than the utility plant efficiency (rising from 40% to 60% in case of gas turbine combined cycle). Trigeneration can be an interesting option for buildings. Payback time basically ranges from 3-4 years in industry, depending on the working hours per year, to 5-6 years for building applications. The cost of natural gas or others fuels and of electricity has a key role in the economic evaluation. 13/26

14 ELECTRICAL SUBSTATIONS - REDUCED LOSS TRANSFORMER Role: conversion of electrical energy,in its electrical parameters Losses: load (depending on the load conditions) and unload (quite constant, depending on voltage level) Tipology: normal losses vs reduced losses Efficiency: rendimento xp η= n xp n +P 0 +x 2 P cn 99.20% 99.00% 98.80% 98.60% 98.40% 98.20% 98.00% 97.80% 97.60% 97.40% 10 % 20 % 30 % 40 % 50 % 60 % 70 % 80 % 90 % 100 % x Column K 14/26

15 ELECTRICAL SUBSTATIONS - REDUCED LOSS TRANSFORMER Although transformer efficiency is quite high (generally not less than 97-98%), it is worth reducing losses by means of reduced-loss transformers with an efficiency improvement of roughly 1% and by a proper choice of the operational zone around the maximum efficiency. 15/26

16 ELECTRICALLY HEATED END-USERS The use of electric energy for heating purposes includes metal treatments, boilers, induction heating, electric arc furnaces, heat pumps, electromagnetic wave heating, mechanical vapor compression. The increasing efficiency of utility plants, from 40% to 60% in the last decade, supports a widespread use of these technologies, mainly: Electromagnetic wave heating Mechanical vapor recompression (MVR) Heat pumps 16/26

17 ELECTRICALLY HEATED END-USERS multiple-effect evaporator with MVR kwh / t steam (dt=6-8 K) at 0.7 MPa specific volume of saturated vapor ~ 2000 m3/t β=pout/pin~1.7 or other prime movers single-effect pin<patm 17/26

18 ELECTRICALLY HEATED END-USERS Heat Pump depending on Hot reservoir temperature COP real ~ 3 Pc=Q H /3 18/26

19 ELECTRICALLY HEATED END-USERS: MECHANICAL VAPOR RECOMPRESSION Payback Years Payback Residential buildings Commercial buildings Current Penetration Future penetration Payback Time Industry Penetration (range 1-5) 19/26

20 ELECTRICALLY HEATED END-USERS: HEAT PUMPS Payback Years Payback Residential buildings Commercial buildings Current Penetration Future penetration Payback Time Industry Penetration (range 1-5) 20/26

21 FACILITIES AIR COMPRESSION PLANTS 6-8 kw > Sm3/min air at 0.7 MPa 21/26

22 FACILITIES AIR COMPRESSION PLANTS 22/26

23 FACILITIES AIR COMPRESSION PLANTS Payback Years Payback Residential buildings Commercial buildings Current Penetration Future penetration Payback Time Industry To save energy: keep the discharge pressure as low as possible carefully avoid mass leaks Penetration (range 1-5) recover heat from cooling systems whenever possible ensure a proper choice and sizing of the compressors and related equipment Savings generally range between 10-20% of the previous consumption with payback times lower than 2 years. Closely dependent on operating conditions, variable speed drive compressors can save up to 30% energy. 23/26

24 ENERGY MANAGEMENT SMART GRID Economic evaluation must take into account a variety of benefits: reduction of regulating power needs by supply-demand matching, advanced fault detection and handling, prevention of critical situation by means of intelligent load shedding, reduction of energy cost for the end-users. 24/26

25 ENERGY MANAGEMENT SMART GRID ICT (Information and Communication Technologies) can create connectivity between a large variety of grid devices, including power production plants, networks nodes and local loads (industry, building and private houses). This research area involves a variety of competences: planning new network architectures allowing bidirectional customers-operators service networks; distributed high-specific power energy storage technologies also for small applications; distributed renewable sources; developing of power electronic devices and cable systems, sensors and monitoring system; Information and Communication Technologies for real-time interaction between suppliers, distributor and customers in the grid. 25/26

26 CONCLUSIONS Energy saving is a difficult goal to achieve because it involves many aspects, technical economic behavioral, which are strictly related and mutually dependent. Energy/power saving is the less expensive and best performing negawatt currently existing. In next decades an estimated 20-30% decrease of specific energy consumption can be foreseen by distributed investments in both industry and buildings. Commercial buildings and residential homes represent the most attractive field for the exploitation of energy saving technologies: in which current consumption can be cut up to 50-60%. 26/26