Retrofit

Retrofitting Strategy	Conversion to radiant cooling technologies (e.g. chilled beam / chilled ceiling) with dedicated air handling system (DAHS)
	Chilled beam/ceiling system incorporates pipes in the false ceilings through which chilled water flows. The pipes lie close to the ceiling surfaces or in panels and cool the room via natural convection and radiation. It operates with higher chilled water temperature, generally 3-5°C higher than the conventional chilled water systems, allowing the chiller evaporator temperature to be correspondingly higher, and thus reducing the chiller energy consumption. It also saves energy by reducing the air flow (only pre-treated fresh air is supplied to the conditioned space) and by handling sensible cooling loads more efficiently.
	Consideration
	Infiltrations have to be controlled to prevent condensation.
	Estimated Saving
	Waterside (Radiant Cooling): (1/COP_CH_PRE – 1/COP_CH_POST)QBLDG_RAD OPHR,yr Where (COP_CH_POST – COP_CH_PRE)/ COP_CH_PRE = 1.25% per 1°C increase of TCHWS COP_CH_POST = [1.25%(TCHWS_POST – TCHWS_PRE) + 1]COP_CH_PRE COP_CH = 0.605COP_CH_SM + 0.395COP_CH_WN COP_CH_SM = (COPa_SM + COPb_SM)/2; COP_CH_WN = (COPa_WN + COPb_WN)/2 QBLDG = 0.605[0.77(0.88NCH_SMQCH_SM + 0.12NCH_WNQCH_WN)] + 0.395[0.596(0.184NCH_SMQCH_SM + 0.816NCH_SMQCH_SM)] QBLDG_RAD = x%QBLDG Airside AHUàDAHS: (SkW_AHU_PRE – SkW_DAHS_POST) OPHR,yr Airside PAU à DOAS: (SkW_PAU_PRE – SkW_DOAS_POST) * OPHR,yr Where SkW_AHU_PRE = (0.605LF_SM,PRE + 0.395LF_WN,PRE)NAHU_PREkW_AHU_PRE SkW_PAU_PRE = (0.605LF_SM,PRE + 0.395LF_WN,PRE)NPAU_PREkW_PAU_PRE SkW_DAHS_POST = (0.605LF_SM,POST + 0.395LF_WN,POST)NDAHS_POSTkW_DAHS_POST SkW_DOAS_POST = (0.605LF_SM,POST + 0.395LF_WN,POST)NDOAS_POSTkW_DOAS_POST For CSD: LF_SM = LF_WN = 1, For VSD: LF_SM = 0.795, LF_WN = 0.562; For EC or DC-motor: LF_SM = 0.71, LF_WN = 0.38 OPHR,yr = hr/dayday/wk52 Please click HERE to view the list of terminology.