3.8.1    Inventory and assessment of pumping systems

The first step towards identifying applicable energy savings measures and optimising a pumping system is to establish an inventory of the pumping systems in the installation with the key operating characteristics. The inventory can be established in two phases (see Section 2.15.1 and Annex 7.7.3):
basic system description: this consists of consulting company records or carrying out simple measurements, in order to assemble the following data:
●list of, e.g. the 50 largest pumps consuming energy (by total pump power rating): size and type
●function of each pumps
●power consumption of each of these pumps
●demand profile: estimated variation during day/week
●type of control system
●operating hours/year, and hence annual energy consumption
●problems or maintenance issues specific to the pump.
In many organisations, most or all of these data could be assembled by in-house staff.
documentation and measurement of the system's operating parameters: documenting or measuring the following elements is desirable for all pumping systems, and is essential for large systems (over 100 kW). Collection of these data will require a significant level of technical expertise, either from in-house engineering staff or from a third party.
Because of the large variety of pumping systems, it is not possible to give a definitive list of points to look for in the assessment, but Sections 3.8.2 to 3.8.6 detail a useful list of key issues to address.

3.8.2    Pump selection

The pump is the heart of the pumping system. Its choice is driven by the need of the process which could be, first of all, a static head and a flowrate. The choice also depends on the system, the liquid, the characteristic of the atmosphere, etc.
In order to obtain an efficient pumping system, the choice of the pump has to be done so as to have an operating point as close as possible to the best efficiency point as indicated in Figure 3.35.

Figure 3.36 shows the ranges of total head as a function of the pump capacity for a given speed in different types of pumps.

It is estimated that 75 % of pumping systems are oversized, many by more than 20 %. Oversized pumps represent the largest single source of wasted pump energy.
When choosing a pump, oversizing is neither cost nor energy efficient as:
●the capital cost is high
●the energy cost is high because more flow is pumped at a higher pressure than required. Energy is wasted from excessive throttling, large by passed f lows, or operation of unnecessary pumps.
Where oversized pumps are identified, their replacement must be evaluated in relation to other possible methods to reduce capacity, such as trimming or changing impellers and/or using variable speed controls. Trimming centrifugal pump impellers is the lowest cost method to correct oversized pumps. The head can be reduced 10 to 50 percent by trimming or changing the pump impeller diameter within the vendor's recommended size limits for the pump casing.

The energy requirements of the overall system can be reduced by the use of a booster pump to provide the high pressure flow to a selected user and allow the remainder of the system to operate a lower pressure and reduced power.

3.8.1    盤點與評估泵輸系統

用以區別泵輸系統可採用的節能方法及優化方式，首先要盤查設施中泵輸系統數量及其操作特性，數量的盤查可以分為兩個階段：
系統的基本描述：包括顧問公司的紀錄或執行簡單的量測，以便蒐集下列資料：
●列明(例如：50個)最大的泵浦的大小、型式、總用電量，將其額定電力加總
●每一泵浦的功能
●每一泵浦的電力消耗值
●需求模式：估列每日及每周的變動
●控制系統的型式
●每年運轉時數及每年能耗量
●對於個別泵浦的問題及維護議題
在某些機構(公司)內，以上資料可由公司內部人員收集。
系統運轉參數文件化及量測：所有泵輸系統，尤其是大型系統(大於100kW)，上列元素希望能文件化及量測。收集這些資料要由高水準的技術專業人員進行，可以是公司內部工程人員或第三方技術人員。
因為泵輸系統間差異性很大，不可能列出固定幾點以供評估，以下3.8.2~3.8.6就有用的關鍵性問題一齊討論。

3.8.2    泵浦的選用

泵浦是泵輸系統的核心，首先它的選用是基於製程的需要、靜壓水頭高度及流量。同時也要考量系統結構、輸送的流體及大氣的特性等。
為了能得到一套有效率的泵輸系統，可以參見圖3.35來選用泵浦，其運轉點盡可能靠近最佳效率的那點。
圖3.36表示不同型式的泵浦在一定轉速下，各泵浦的功能以水頭高度表現時的區間範圍。
顯然有75%的泵輸系統是過大的，部分還大了20%。過大的泵浦規格是泵浦浪費能源的最大源頭。
選用過大規格的泵浦既不省錢也不節能：
●投入資本很高
●能源成本很高，因為迸出的流量超過其需要的壓力。超過的流量和壓力將之節流及調壓或由旁通閥回流，或讓不需要的泵浦運轉等是很浪費能源的。
當確認泵浦過大規格時所需做更換處置前，必須先評鑑其是否可以其他方法來降低容量，例如調整或更改轉子葉片或使用變速控制。調整轉子葉片是離心泵浦改正規格過大最省錢的方法。在供應商建議的外殼尺寸限制內調整轉子葉片直徑，其水頭高度可以降低10~50%。
利用一台增壓泵浦提供高壓流量給特定使用者，而其他系統內使用者則使用較低壓且不需要太大動力的流體，這樣可以減少整體泵輸系統需要的能源。

None reported.

無資料。

The applicability of particular measures, and the extent of cost savings depend upon the size and specific nature of the installation and system. Only an assessment of a system and the installation needs can determine which measures provide the correct cost-benefit. This could be done by a qualified pumping system service provider or by qualified in-house engineering staff.
The assessment conclusions will identify the measures that are applicable to a system, and will include an estimate of the savings, the cost of the measure, as well as the payback time.

一些特別的使用方法及節省的成本端視設施和系統的規模與特性而定。只有評鑑過系統及設施才能決定其正確的成本效益。此評鑑可由合格的泵輸系統服務供應商或合格的公司內部工程師來執行。
評鑑結論可用來辨明系統該使用何種方法、估計節省的成本、實施成本及回收年限等資料。

Pumping systems often have a lifespan of 15 to 20 years, so a consideration of lifetime costs against initial (purchase) costs are important.
Pumps are typically purchased as individual components, although they provide a service only when operating as part of the system, so a consideration of the system is important to enable a proper assessment of the cost-benefit.

通常泵浦系統有較長的使用年限(15~20年)，所以全使用年限的成本和初設成本間的考量是很重要的。
一般而言，泵浦都是單獨採購的，雖然在系統內可提供部分功能，但系統在評估成本效益時，泵浦的購置成本應考量在內。

Energy Efficiency (2009) 3.8.1、3.8.2